Ann Thorac Surg 1997;64:739-745
© 1997 The Society of Thoracic Surgeons
Original Article: General Thoracic
Septal Myectomy in Hypertrophic Obstructive Cardiomyopathy: Late Results With Stress Echocardiography
M. Kamil Göl, MD,
Mustafa Emir, MD,
Talat Kele
, MD,
eref A. Küçüker, MD,
C. Levent Birincio
lu, MD,
Y. Haldun Karagöz, MD,
Tevfik Kural, MD,
Ouz Tademir, MD,
Siber Göksel, MD,
Kemal Bayazit, MD
Cardiovascular Surgery Clinic and Cardiology Clinic, Türkiye Yüksek 
htisas Hospital, Ankara, Turkey
Accepted for publication March 22, 1997.
 |
Abstract
|
|---|
Background. This study was performed to assess the functional capacity of the survivors of septal myectomy for the treatment of hypertrophic obstructive cardiomyopathy in long-term follow-up as assessed by dobutamine stress echocardiography.
Methods. Sixty-nine patients with hypertrophic obstructive cardiomyopathy underwent septal myectomy between 1975 and 1996. The mean age was 25.4 ± 13.6 years (range, 6–58 years), and 10 of the patients were women. The early mortality was 4.3%. Hospital survivors (95.7%) were followed up for a mean of 43.8 ± 28.7 months (range, 6–114 months).
Results. The postoperative mean functional capacity of the group was 1.47 ± 0.56. No late deaths were reported. Forty-nine patients (74.2%) were evaluated with standard echocardiographic techniques, and 29 (43.9%) patients underwent dobutamine stress echocardiography. There was a significant decrease in the thickness of the interventricular septum after surgery. The mean preoperative and postoperative septal thickness was 1.99 ± 0.59 cm (range, 1.3–3.8 cm) and 1.55 ± 0.41 cm (range, 0.96–2.8 cm), respectively (p < 0.004). The mean posterior wall thickness was significantly less than the preoperative value (p = 0.008) and the left ventricular end-diastolic diameter was slightly greater in the postoperative measurements, but the difference was not significant (p = 0.162). Postoperative left ventricular outflow systolic gradients were reduced significantly when compared with preoperative values (preoperative mean, 78.4 ± 33.6 mm Hg, range, 50–212 mm Hg versus postoperative mean, 17.9 ± 15.9 mm Hg; range, 0–40 mm Hg; p < 0.0001).
Conclusion. Septal myectomy for patients with hypertrophic obstructive cardiomyopathy is a safe procedure with excellent clinical and functional results in the long-term follow-up.
|
Introduction
|
|---|
Hypertrophic obstructive cardiomyopathy (HOCM) or, as it was once named by Braunwald and associates, "idiopathic hypertrophic subaortic stenosis," is a well-known pathology in which there is a primary hypertrophy of cardiac muscle with increased systolic but impaired diastolic function of the heart [1]. The etiology is unknown, but autosomal dominant inheritance was also tracked in some families [2]. Morphologically, HOCM is characterized by the asymmetrical hypertrophy of the interventricular septum with bizarrely shaped and disorganized cardiac muscle fibers and increased areas of interstitial connective tissue [3]. There is an obstruction of the left ventricular outflow tract (LVOT), which is associated with the systolic anterior motion of the anterior mitral leaflet. Various types of LVOT obstruction caused by mitral anterior leaflet were also reported by different authors [4, 5].
Treatment of patients with HOCM includes mitral valve replacement [6], ß-blocking agents and calcium channel blockers [7, 8], antiarrhythmics [9], and recently dual chamber pacing [10]. All of these treatments have their own pros and cons or still need further evaluations, but the surgical treatment of HOCM, transaortic left ventricular myectomy/myotomy, as originally described by Morrow and associates [11], is usually spared for those patients who are mildly symptomatic or have more than 50 mm Hg systolic LVOT gradients at rest or after provocative tests. Early improvements in clinical status, hemodynamics, and physical capacity after surgical treatment of LVOT obstructions in patients with HOCM has been documented several times [12–16]. The aim of the present study was to evaluate the patients' functional capacity in the late follow-up with a provocative test, dobutamine stress echocardiography, for the determination of the LVOT gradient, which is a reliable indicator of the stress produced during exercise.
|
Material and Methods
|
|---|
Study Patients
Between 1975 and 1996, 115 consecutive patients with subaortic stenosis were operated on at the Cardiovascular Surgery Clinic of Türkiye Yüksek htisas Hospital. Of these, 69 were assigned to the diagnosis of HOCM. Ten of the HOCM patients were women (14.5%) and 59 patients were men, with the total group having a mean age of 25.40 ± 13.62 years (range, 6–58 years). The preoperative functional capacities according to New York Heart Association (NYHA) classification are given in Table 1
. Thirty-eight patients (55.1%) were in NYHA class III, 24 (34.8%) were in NYHA class II, and 7 patients (10.1%) were in NYHA class I. The most prevalent symptoms were exertional dyspnea in 54 of the patients (78.2%) and angina pectoris in 29 of the patients (42.0%). Dizzy spells were present in 14 patients (20.3%), and syncope history was recorded in 19 patients (27.5%). Two patients were asymptomatic. Actually, 7 patients who were classified as NYHA class I did not have symptoms other than the complaint of dizzy spells on more than one occasion.
The preoperative diagnosis was made with catheterization alone in 4 patients and with only echocardiography in 23 patients. In the remaining 42 patients, both echocardiography and hemodynamic study were used for the proper diagnosis. After 1984, Doppler echocardiographic evaluation of patients was used in addition to M-mode and two dimensional echocardiographic studies. Coronary arteriography was performed for all patients older than 40 years.
|
Indications for Operation
|
|---|
Patients with a significant LVOT obstruction (systolic gradient higher than 50 mm Hg) were assigned for operation. Patients who formed the marginal group for operation (those who do not have significant LVOT systolic gradients at rest, but exhibit it after provocative tests) were treated with ß-blocking agents or calcium channel blockers, sometimes in combination, before the indication for operation was decided. Patients who had symptoms despite medical treatment or evidence of LVOT obstruction at rest or exercise during medical treatment were recommended for operation.
|
Preoperative Echocardiographic and Hemodynamic Findings
|
|---|
Sixty-five patients underwent preoperative echocardiographic evaluation. The LVOT systolic gradient, which was measured echocardiographically, ranged between 40 and 212 mm Hg (mean, 75.3 ± 52.4 mm Hg). Preoperative measurements of the interventricular septum ranged between 1.3 and 4.0 cm (mean, 2.01 ± 1.04 cm). The thickness of the left ventricular posterior wall ranged between 0.9 and 2.8 cm (mean, 1.67 ± 0.44 cm). Left ventricular diastolic diameter ranged between 1.9 and 5.2 cm (mean, 3.91 ± 1.22 cm). In 12 patients, subaortic membranes were detected, such that it was not possible to measure any LVOT gradients. In 6 patients discrete subaortic membranes were also found.
Systolic anterior motion of the mitral valve was present in 61 patients. Mitral insufficiency was present in 39 patients. In 6 of these, the degree of the regurgitation was more than moderate. In 1 patient, anomalous insertion of mitral valve causing LVOT obstruction was detected. Bicuspid aortic valve was found in 10 male patients. Six of these bicuspid aortic valves were causing mild stenosis. The gradient that was measured at the level of the aortic valve leaflets by echocardiography ranged between 15 and 35 mm Hg. In 2 additional patients, there was significant aortic insufficiency. Ventricular septal defects were detected in 4 patients by echocardiography. All of these defects were classified as inflow perimembranous defects. In 2 patients, evidence that suggested patent ductus arteriosus was detected.
Hemodynamic findings of 42 patients, who were also evaluated by echocardiography, were in good correlation with the echocardiographic findings. The LVOT systolic gradients ranged between 50 and 200 mm Hg (mean, 70.9 ± 61.1 mm Hg). Four other patients were evaluated only by hemodynamic studies. In these 4 patients, LVOT systolic gradients were 75, 80, 110, and 138 mm Hg.
Hemodynamic studies revealed one additional ventricular septal defect, in addition to the ones that were detected by echocardiography. In 2 other patients, coarctations of the aorta were also found with LVOT systolic gradients of 35 and 60 mm Hg. In 1 additional patient, patent ductus arteriosus was found.
|
Surgical Technique
|
|---|
After exposure of the heart through a median sternotomy, extracorporeal circulation was instituted with aortic and bicaval canulation through the right atrium. Cardiopulmonary bypass was commenced with systemic cooling to approximately 28° to 32°C. For myocardial arrest, crystalloid cardioplegia, administered into the aortic root after cross-clamping, was used until 1987, but after that, retrograde hypothermic blood cardioplegia after initial antegrade hypothermic crystalloid cardioplegic arrest (St. Thomas Hospital solution II) was used, and terminal warm blood cardioplegia was given before removal of aortic cross-clamps.
An oblique aortic incision extending to the noncoronary sinus was used to visualize and inspect the aortic valve and subvalvular septum. After retraction of the intact aortic cusps, the hypertrophied septum and the anterior mitral leaflet became visible. The first incision to the myocardium was made beneath the commissure of the left and right coronary cusps, and the second was made 1 to 2 mm to the right of the nadir of the right coronary cusp in the left ventricular apical direction. The muscle bar, approximately 1-cm thick and 1 to 2 cm in width, that extends 3 to 5 cm toward the apex was resected between the incisions. The resection was extended toward the left ventricular apex until the bases of the papillary muscles were seen. Clear visibility of the papillary muscles was considered as a promising sign of adequate relief of LVOT obstruction. After repeated rinsing of the left ventricle, and completion of the associated procedures, the aortic root was closed with continuous whip sutures. The patient was weaned from cardiopulmonary bypass after rewarming. Pressures of the left ventricle and aortic root were measured directly to see if any significant gradient still existed. If this was the case, cardiopulmonary bypass was recommenced for further myectomy.
In the last 13 operations, transesophageal echocardiography (TEE) was used to assess the LVOT before the institution of cardiopulmonary bypass and to check for residual obstructions before coming off the pump. In 2 patients, significant residual gradients in the LVOT were noticed and the aorta was reopened for more extensive resections. Also iatrogenic ventricular septal defects were found during the intraoperative TEE examination in 2 patients, which were closed before completing the operation.
|
Follow-up
|
|---|
Complete follow-up was achieved with a mean of 43.8 ± 28.7 months (range, 6–114 months) with direct patient interview. No late deaths were recorded for 66 hospital survivors of this series. Forty-nine patients (74.2%) were evaluated with standard echocardiographic techniques, and the ones who accepted the dobutamine test (n = 32) underwent the following test protocol.
|
Dobutamine Stress Echocardiography Test Protocol
|
|---|
After the basal state measurements were made for the patients with the two-dimensional and Doppler echocardiographic techniques, dobutamine infusion was started with a dose of 2.5 µg • kg-1 • min-1 in patients who did not have any severe obstruction in the LVOT under resting conditions. This test was modified from the protocol of Bruce and McDonough [17]. Dobutamine infusion rate was increased every 3 minutes until the desired maximal heart rate was achieved. The dose increments were 5, 10, 15, 20, 25, 30, and 40 µg • kg-1 • min-1, respectively. Echocardiographic evaluation and recordings were made for every dose increment. After reaching the maximal heart rate, measurements during the recovery period were repeated until the resting conditions were regained for 3 minutes.
|
Statistical Analysis
|
|---|
Mean ± standard deviation values were given for continuous variables and were analyzed using the Student's t test for paired variables. The 
2 or Fisher's exact test was used to compare discontinuous variables.
|
Results
|
|---|
Early Results
The overall 30-day operative mortality rate was 4.3% (3/69). One of these deaths was a result of left ventricular rupture that occurred during the resuscitative efforts for the intractable ventricular fibrillation in the sixth postoperative hour that did not respond to electrical defibrillation or medications. One patient died as a result of low cardiac output in the early postoperative period. In another patient, myectomy did not relieve the diffuse LVOT obstruction, and aortoventriculoplasty was added to the procedure. This was a female patient, who was 49 years old, with 135 mm Hg systolic gradient at the LVOT. Her height was 151 cm, and she weighed 42 kg. The preoperative thickness of the septum was measured at 3.8 cm, and the left ventricular posterior wall thickness was 2.8 cm. The end-diastolic diameter was measured at 3.6 cm. It was not possible to wean the patient from cardiopulmonary bypass.
In 18 patients (26.1%) subvalvular fibrotic membranes were also removed. Twelve of these were detected by echocardiography, but were not causing any significant obstruction. They were more like fibrous plaques, probably caused by the turbulence in the LVOT. In 6 patients, actual discrete subaortic membranes were found and removed. Four patients needed mitral annuloplasty because of organic lesions of the mitral valve. In 3 patients mitral valve replacement (MVR) with mechanical prosthetic valves was performed. One of these patients was reported previously as having an anomalous insertion of a hypertrophied papillary muscle of the mitral valve, which caused LVOT obstruction, and a muscular bridge causing narrowing of the left anterior descending artery [5]. There were organic lesions of aortic valves in 8 patients. Six of these, who had bicuspid aortic valves with some degree of stenosis, were treated with aortic valvotomy, but 2 patients with severe aortic insufficiency had to be treated with valve replacement.
In a 19-year-old female patient, septal myectomy resulted in residual severe stenosis of the LVOT, and an apico-aortic valved conduit that contained a Björk-Shiley valve was placed between the left ventricular apex and descending aorta. This patient was later admitted to the hospital three times, 3, 5, and 6 months postoperatively, with recurrent emboli to the femoral arteries that required embolectomy. In the sixth postoperative month, the apico-aortic conduit was removed. She was offered another operation for the residual stenosis in the LVOT, but she did not accept the reoperation. She was followed up for an additional 62 months with a resting systolic gradient of 65 mm Hg.
Associated procedures are given in Table 2. In 7 patients ventricular septal defects were repaired, 3 of which required patches. Two iatrogenic defects were discovered with TEE and were repaired with primary pledgeted sutures.
|
Late Results
|
|---|
Long-term follow-up was achieved for all the hospital survivors with a mean of 43.8 ± 28.7 months (range, 6–114 months) with direct patient interview. No deaths in the late term were recorded. Actuarial survival after 72 months was 95.6%, including hospital deaths. The mean functional capacity of this group was 1.47 ± 0.56. Thirty-seven patients (56%) were recorded as NYHA class I and 27 (40.9%) were in NYHA class II (Table 1
). Of the 66 hospital survivors, 12 were using ß-blocking agents, 9 were using calcium-channel blockers, and 4 were using these drugs in combination. Forty-one patients (54.9%) were using neither of them.
In the late term 3 patients were reoperated on. One of the patients was operated on for aortic valve endocarditis in the tenth postoperative month and aortic valve replacement was performed. Another patient underwent aortic valve replacement in the 12th postoperative month because of severe systolic gradient of the aortic valve. A third reoperation was an aortic valvotomy because of restenosis of the aortic valve in the 12th postoperative month. All 3 patients are alive and are NYHA class I. Besides the preceding reoperations, the patient who had an apico-aortic conduit was reoperated on for the removal of the conduit because of the recurrent embolic episodes.
Forty-nine patients were invited to the hospital for dobutamine stress echocardiography. All of them responded to our invitation, but 32 patients accepted the test. Seventeen patients did not accept the test and were evaluated with two-dimensional and Doppler echocardiography in the resting conditions. In 3 cases of those who accepted the dobutamine test, severe aortic valvular gradients were measured during the resting state, and they were not allowed further evaluations with dobutamine infusions. These patients were in NYHA class I, but, in 2 of them who were in their 46th and 65th postoperative months, the systolic aortic valvular gradient was more than 75 mm Hg; they were scheduled for reoperation. The third patient had a 45-mm Hg aortic valvular gradient, was symptomless, and in the 36th postoperative month; she is maintained to close follow-up schedules. None of those 20 patients who did not undergo the dobutamine stress echocardiography have any subvalvular gradient. Systolic anterior motion of the mitral valve was found in 5, and they have undergone hemodynamic studies. However, the hemodynamic studies did not reveal any subaortic obstruction.
Preoperative and postoperative echocardiographic measurements in the resting state of the 49 patients are given in Table 3. There is a significant decrease in the thickness of the interventricular septum. The mean preoperative septal thickness was 1.99 ± 0.59 cm (range, 1.3–3.8 cm), and the mean postoperative septal thickness was 1.55 ± 0.41 cm (range, 0.96–2.8 cm) (p < 0.004). The measurements for the posterior wall thickness also revealed a statistically significant decrement. The mean posterior wall thickness was significantly less than the preoperative value (p = 0.008). Left ventricular end-diastolic diameter was slightly greater in the postoperative measurements, but it did not reach statistical significance (p = 0.162).
|
Dobutamine Stress Echocardiography
|
|---|
Twenty-nine patients underwent this test. The mean follow-up for this subgroup of patients was 64.3 ± 31.3 months (range, 13–110 months). In 4 patients it was not possible to reach the desired maximal heart rate, probably because of the medications that the patients were taking. In these cases, a submaximal effort capacity was reached. Ectopic ventricular beats were noticed and recorded in 5 patients. One of these patients also had angina during the test, and the dopamine infusion was abandoned before reaching the end point. This patient did not exhibit any subvalvular or valvular gradient during the test, but his age was 51 years and he is scheduled for coronary arteriography. In the remaining 4 patients who had ectopic beats, the tests were completed. Two other patients who did not have any evidence of LVOT obstruction in the resting state exhibited severe subvalvular gradients and systolic strain pattern in the electrocardiogram during the test, and the test was discontinued.
In the 26 patients who completed the test, none of them exhibited systolic LVOT obstruction. However, 1 male patient, who is in the seventh postoperative year of his follow-up, had a 75-mm Hg systolic gradient during the recovery period. This patient underwent hemodynamic study with provocation 1 month later, but this did not reveal any significant LVOT obstruction. He was in NYHA class I and taking no medications. Calcium channel blockers were prescribed to this patient and he was advised to keep in close contact with the hospital.
|
Comment
|
|---|
Surgical treatment of HOCM is an accepted option of therapy with proven low early and late mortality, in addition to significant improvements in the late term functional capacity [11–16]. The early mortality in the current series was 4.3%, which is within acceptable ranges that are given in the literature. Heric and colleagues [15] reached the conclusion that associated procedures such as coronary artery bypass grafting combined with mitral valve replacement in patients who have undergone myotomy/myectomy were predictors of hospital mortality. We had one death in the group of patients who had associated procedures. This was in a patient who had undergone aortoventriculoplasty. The other two deaths were in patients who did not have any associated procedures. When procedures such as mitral valve repair or replacement, aortic valve repair or replacement, aortoventriculoplasty, tricuspid annuloplasty, and coronary artery bypass grafting are taken into account, which could affect the early outcome (n = 18), there was not any significant difference in mortality compared with the rest of the group (5.6% versus 3.9%, p = 0.699).
Mitral valve replacement was proposed as the favored option of therapy by Cooley and associates [6, 18]. It is generally accepted that a Venturi effect causes systolic anterior motion of the anterior leaflet of the mitral valve and results in LVOT obstruction to a variable degree. The goal of this operation is to increase the cross-sectional area of the LVOT by moving the mitral leaflet out of the way and alleviating the systolic gradient. Additionally, the replacement of the mitral valve would also end up with the elimination of the mitral regurgitation. Cooper and associates recommended mitral valve replacement in the following cases: in the presence of a thin septum less than 18 mm, in the presence of atypical septal structure, after previous septal myectomy, and in the presence of intrinsic mitral valve disease [19]. In our clinic practice mitral valve replacement has not been the first therapeutic option for treatment of HOCM. The mitral valve was repaired or replaced in patients who have intrinsic mitral valve disease in addition to HOCM. In only 1 reported patient, mitral valve replacement was taken as the first choice [4]. The general tendency in the literature seems to be similar to our approach [13–16].
It was stated in the review by Schulte and associates [13] that the expected late mortality after surgical treatment of HOCM ranges between 0.6% and 1.6% per year; this figure is estimated to be 0.6% per year in the work of Heric and associates [15]. In their retrospective review Robbins and Stinson [16] report a 0.5% per year mortality in the late follow-up. We did not calculate any late term mortality figure because there were no late deaths recorded in our follow-up. This is consistent with the conclusion that septal myectomy has better results in the long-term. The reported late deaths are usually associated with ventricular arrhythmias, and although amiodarone was offered, still a controversy exists. Heric and associates [15] found that the preoperative use of amiodarone was an independent risk factor for perioperative mortality.
There has been a concern in the previous works that septal myectomy may result in significant aortic insufficiency, a situation that we did not encounter. Brown and associates [20] reported 4% aortic insufficiency in the late term. The only significant aortic insufficiency recorded in our series was caused by endocarditis.
Seiler and associates [12] concluded that the most favorable outcome was observed in surgically treated patients receiving long-term therapy with verapamil. Verapamil has also been reported to have comparable results with surgically treated patients when chosen as the primary mode of therapy [8]. Gwathmey and colleagues [21] measured the electrophysiologic and isometric properties of myocardium removed at myectomy and transplantation to test the hypothesis that intracellular calcium overload underlies the diastolic dysfunction of patients with hypertrophic cardiomyopathy. Action potentials, calcium transients, and isometric contraction and relaxation were markedly prolonged in the hypertrophied myocardium. At 1 Hz pacing frequency, a state of relative calcium overload appeared to develop, which produced a rise in end-diastolic intracellular calcium, incomplete relaxation, and a decrease in active tension development. These abnormalities were exacerbated by digitalis and prevented by verapamil. The study of Camici and associates [22] demonstrated abnormal coronary vasodilator reserve in both hypertrophied and nonhypertrophied segments of the left ventricular myocardium, suggesting a primary defect (not secondary to hypertrophy) in coronary vasomotion. All these findings suggest that surgical therapy of HOCM accompanied by calcium channel blockers in the long-term should have the most favorable outcome.
Surgical therapy of HOCM resulted in improvement in functional class or symptoms in 97% of our surviving patients. These results are similar to the experience of other authors [12–16]. In addition to this subjective criteria, the dobutamine stress echocardiography also showed that exercise capacity of the surgically treated HOCM patients was improved and had not deteriorated in the long term as a result of the nature of the disease itself. Actually, dobutamine stress echocardiography may not be practical to evaluate patients in the postoperative follow-up, especially when they are in good condition, but this study was designed for the scientific purpose of evaluating the exercise capacity of patients who have undergone myectomy. Provocative tests have been used in the literature for evaluation of these patients preoperatively or postoperatively. In a study by Klues and associates [23], it was found that in patients with hypertrophic cardiomyopathy, LVOT obstruction developed in the recovery period of exercise testing, which was explained with the rapid fall in the preload and systemic vascular resistance after the cessation of exercise done in the supine position. This mechanism was considered to be one of the reasons for sudden cardiac death after exercise in patients with this disease. This phenomenon was observed in one of our patients in the recovery period of dobutamine stress echocardiography, but the hemodynamic study of this patient did not reveal any significant LVOT obstruction. It might also indicate the favorable results of septal myectomy in which the decrease in preload and systemic vascular resistance does not result in LVOT obstruction.
Whether septal myectomy that effectively relieves LVOT obstruction also ameliorates left ventricular stiffness remains controversial, partially because of the difficulty of accurately assessing the left ventricular diastolic function. In the study by Chikamori and associates [24], it is concluded that in patients with hypertrophic cardiomyopathy that have LVOT gradient at rest, main determinants of exercise limitation were impaired left ventricular and left atrial systolic performance. However, in the same study, it was stated that in those patients without a gradient, diastolic function was a more important factor for the limitation of exercise performance. Also, in the report by Nihoyannopoulos and colleagues [25], 77% of patients with a poor response to cardiopulmonary exercise testing also had impaired Doppler diastolic indices at rest. When these works are taken into account, the excellent exercise capacity that is found after dobutamine stress echocardiography in our series of patients indicates a good diastolic performance as well as systolic capacity. Despite the fact that diastolic parameters, other than the diastolic diameter of the left ventricle, were not measured because exercise capacity is also a good indicator of the diastolic functions, it can be concluded that the relief of the LVOT obstruction tends to improve the left ventricular diastolic functions.
The treatment of hypertrophic cardiomyopathy is not a concern of this work. Actually there are universally accepted therapies, including ß-blockers and calcium channel blockers. Controversy exists in the treatment of HOCM, especially when the patient is not an obvious case for surgery. These marginal patients, who do not have significant gradients at rest and develop mild to moderate obstruction after provocation, or who have 50 to 60 mm Hg systolic gradient at rest and after provocation, and the mildly symptomatic patients or those with no symptoms at all form the hard to decide group. It is our belief, which has support in the literature, that these patients should be electively operated on. The obstruction of the outflow is dynamic and progressive, causing the "shrinkage" of the left ventricular cavity. It might stay asymptomatic for a long time as long as the patient has a sedentary life style. Medical treatment has 5% to 7% outcome of death per year. We think it is justifiable to operate on patients who are in the hard to decide group because the long-term results of septal myectomy are excellent [12, 15].
Although the work of Fananapazir and colleagues [10] indicates that dual-chamber pacing has results comparable with the other modes of therapy, the results of our study do not allow us to further comment on the subject. A review of the literature indicates the need for further evaluation [15, 16].
Iatrogenic ventricular septal defect has been reported in 3% of patients by Kirklin and Barratt-Boyes [1]. We found it in 2 patients who had it detected by TEE before completion of the operation, and were repaired without any further complication. In the latest 13 patients of our series TEE was used, and will be routinely used in the future patients of our clinic. This is also proposed by many authors [15]. However, in the patients who were operated on in the era when TEE was not available, any residual or iatrogenic ventricular septal defect was not recorded in the postoperative echocardiographic evaluation of our cases. This might imply that, if there were any iatrogenic ventricular septal defects, they were too small to cause any significant shunt and tended to close spontaneously in the postoperative period, or that there were none at all. Intraoperative assessment of the outflow tract and evaluation of the mitral valve in the working heart with Doppler echocardiography is a tool for the surgeon that cannot be ignored.
In conclusion, septal myectomy is still the treatment of choice for patients with HOCM with a significant gradient in the LVOT and symptoms that are refractory to medical therapy. It is a very safe and effective procedure with excellent clinical, echocardiographic follow-up and exercise capacity in the long term.
|
Footnotes
|
|---|
Address reprint requests to Dr Göl, Cardiovascular Surgery Clinic, Türkiye Yüksek htisas Hospital, 06100 Sihhiye, Ankara, Turkey (e-mail: hk04-k{at}servis.net.tr).
|
References
|
|---|
- Kirklin JW, Barratt-Boyes BG. Hypertrophic obstructive cardiomyopathy. In: Kirklin JW, Barratt-Boyes BG, eds. Cardiac surgery. Morphology, diagnostic criteria, natural history, techniques, results and indications, vol. 2, 2nd ed. New York: Churchill Livingstone, 1993:1239–62.
- Hejtmancik JF, Brink PA, Towbin J, et al. Localization of gene for familial hypertrophic cardiomyopathy to chromosome 14q1 in a diverse US population. Circulation 1991;83:1592–7.[Abstract/Free Full Text]
- Factor SM, Butany J, Sole MJ, Wigle ED, Williams WC, Rojkind M. Pathologic fibrosis and matrix connective tissue in the subaortic myocardium of patients with hypertrophic cardiomyopathy. J Am Coll Cardiol 1991;17:1343–51.[Abstract]
- Tademir O, Küçükaksu DS, Kural T, Bayazit K. Hypertrophic obstructive cardiomyopathy in combination with anomalous insertion of papillary muscle directly into anterior mitral leaflet and "Sawfish" systolic narrowing of the left anterior descending coronary artery. Tex Heart Inst J 1994;21:317–20.[Medline]
- Björk VO, Hultquist G, Lodin H. Subaortic stenosis produced by an abnormally placed anterior mitral leaflet. J Thorac Cardiovasc Surg 1961;41:659–69.
- Cooley DA, Leachman RD, Hallman GL, Gerami S, Hall RJ. Idiopathic hypertrophic subaortic stenosis: surgical treatment including mitral valve replacement. Arch Surg 1971;103:606–9.[Medline]
- Flamm MD, Harrison DC, Hancock EW. Muscular subaortic stenosis: prevention of outflow obstruction with propranolol. Circulation 1968;38:846–58.[Abstract/Free Full Text]
- Bonow RO, Dilsizian V, Rosing DR, Maron BJ, Bacharach SL, Green MV. Verapamil-induced improvement in left ventricular diastolic filling and increased exercise tolerance in patients with hypertrophic cardiomyopathy: short- and long-term effect. Circulation 1985;72:853–64.[Abstract/Free Full Text]
- Frenneaux MP, Counihan PJ, Porter A, Lipkin DP, McKenna WJ. Effects of amiodarone on erect and supine exercise haemodynamics and exercise capacity in patients with hypertrophic cardiomyopathy. Eur Heart J 1992;13:687–96.[Abstract/Free Full Text]
- Fananapazir L, Canon RO III, Tripodi D, Panza JA. Impact of dual-chamber permanent pacing in patients with obstructive hypertrophic cardiomyopathy with symptoms refractory to verapamil and ß-adrenergic blocker therapy. Circulation 1992;85:2149–61.[Abstract/Free Full Text]
- Morrow AG, Reitz BA, Epstein SE, et al. Operative treatment in hypertrophic subaortic stenosis: techniques, and the results of pre and postoperative assessments in 83 patients. Circulation 1975;52:88–102.[Abstract/Free Full Text]
- Seiler C, Hess OM, Schoenbeck M, et al. Long term follow-up of medical versus surgical therapy for hypertrophic cardiomyopathy: a retrospective study. J Am Coll Cardiol 1991;17:634–42.[Abstract]
- Schulte HD, Bircks WH, Loesse B, Godehardt EAJ, Schwartzkopff B. Prognosis of patients with hypertrophic obstructive cardiomyopathy after transaortic myectomy: late results up to twenty-five years. J Thorac Cardiovasc Surg 1993;106:709–17.[Abstract]
- Ten Berg JM, Suttorp MJ, Knaepen PJ, Ernst SMPG, Vermeulen FEE, Jaarsma W. Hypertrophic obstructive cardiomyopathy: initial results and long-term follow-up after Morrow septal myectomy. Circulation 1994;90:1781–5.[Abstract/Free Full Text]
- Heric B, Lytle BW, Miller DP, Rosenkranz ER, Lever HM, Cosgrove DM. Surgical management of hypertrophic obstructive cardiomyopathy, early and late results. J Thorac Cardiovasc Surg 1995;110:195–208.[Abstract/Free Full Text]
- Robbins RC, Stinson EB. Long-term results of left ventricular myotomy and myectomy for obstructive hypertrophic cardiomyopathy. J Thorac Cardiovasc Surg 1996;111:586–94.[Abstract/Free Full Text]
- Bruce RA, McDonough JR. Stress testing for cardiovascular disease. Bull N Y Acad Med 1969;45:1288–94.[Medline]
- Cooley DA, Wukasch DC, Leachman RD. Mitral valve replacement for idiopathic hypertrophic subaortic stenosis; results in 27 patients. J Cardiovasc Surg 1976;17:380–7.[Medline]
- Cooper MM, Tucker E, McIntosh CL, Cannon RO, Clark RE. Effect of left ventricular septal myectomy on concurrent mitral regurgitation. Ann Thorac Surg 1989;48:251–6.[Abstract]
- Brown PS, Roberts CS, McIntosh CL, Clark RE. Aortic regurgitation after left ventricular myotomy and myectomy. Ann Thorac Surg 1991;51:585–92.[Abstract]
- Gwathmey JK, Warren SE, Briggs GM, et al. Diastolic dysfunction in hypertrophic cardiomyopathy. J Clin Invest 1991;87:1023–31.[Medline]
- Camici P, Chiriatti G, Lorenzoni R, et al. Coronary vasodilation is impaired in both hypertrophied and non-hypertrophied myocardium of patients with hypertrophic cardiomyopathy: a study with nitrogen-13 ammonia and positron tomography. J Am Coll Cardiol 1991;17:879–86.[Abstract]
- Klues HG, Leuner C, Kuhn H. Left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy: increase in gradient after exercise. J Am Coll Cardiol 1992;19:527–33.[Abstract]
- Chikamori T, Counihan PJ, Doi YL, et al. Mechanisms of exercise limitation in hypertrophic cardiomyopathy. J Am Coll Cardiol 1992;19:507–12.[Abstract]
- Nihoyannopoulos P, Karatasakis G, Frenneaux M, McKenna WJ, Oakley CM. Diastolic function in hypertrophic cardiomyopathy: relation to exercise capacity. J Am Coll Cardiol 1992;19:536–40.[Abstract]
This article has been cited by other articles:
|
|
|
|
 
V. L. Fernandes, C. Nielsen, S. F. Nagueh, A. E. Herrin, C. Slifka, J. Franklin, and W. H. Spencer III
Follow-Up of Alcohol Septal Ablation for Symptomatic Hypertrophic Obstructive Cardiomyopathy: The Baylor and Medical University of South Carolina Experience 1996 to 2007
J. Am. Coll. Cardiol. Intv.,
October 1, 2008;
1(5):
561 - 570.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
K. Okeie, M. Shimizu, H. Yoshio, H. Ino, M. Yamaguchi, T. Matsuyama, T. Yasuda, J. Taki, and H. Mabuchi
Left ventricular systolic dysfunction during exercise and dobutamine stress in patients with hypertrophic cardiomyopathy
J. Am. Coll. Cardiol.,
September 1, 2000;
36(3):
856 - 863.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
