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Ann Thorac Surg 1999;68:887-893
© 1999 The Society of Thoracic Surgeons

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Original Articles: Cardiovascular

Cardiovascular operations in patients with dialysis-dependent renal failure

^a Department of Thoracic and Cardiovascular Surgery, Heart Center Duisburg, Duisburg, Germany

Address reprint requests to Dr Frenken, Chirurgische Abteilung, Städtisches Krankenhaus Düsseldorf-Gerresheim, Gräulingerstrasse 120, 40625 Düsseldorf, Germany

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
Background. Cardiac operations in patients with end-stage renal disease carry a significantly increased perioperative risk, and long-term functional results and survival are still purely defined.

Methods. Therefore, we performed a retrospective analysis of 45 consecutive patients with dialysis-dependent renal failure who underwent either coronary artery bypass grafting (n = 30), valve replacement or combined procedures (n = 13), or pericardiotomy (n = 2). Mean age of the patients was 59 ± 10 years.

Results. There were two perioperative deaths (30-day mortality, 4.4%). Actuarial survival rates at 1, 2, 3, and 5 years were 0.90, 0.73, 0.67, and 0.67, respectively, after bypass operation and 0.77, 0.77, 0.77, and 0.39, respectively, after valvular or combined operation. Late deaths (n = 13) occurred 2 to 60 months after operation and were attributable to cardiac events in 7 patients. Of the long-term survivors after either bypass grafting (n = 20) or a valvular or combined procedure (n = 8), 15 and 7 patients had improved anginal status and New York Heart Association functional status, respectively, after 36 ± 4 months (range, 21 to 66 months). Five patients underwent renal transplantation 32 ± 9 months after cardiac operation.

Conclusions. Cardiac operations in patients with end-stage renal disease may be performed with a fairly low perioperative risk and the perspective of long-term functional improvement and acceptable long-term survival.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
Myocardial infarction and other cardiac events are the leading causes of mortality in the population of patients who are on maintenance dialysis due to end-stage renal disease [1]. Both for functional and for vital reasons a cardiac operation is often considered necessary to improve life quality and prolong life expectancy, especially in patients suffering from coronary artery disease [1–6], valvular stenosis [6, 7] or acute endocarditis [3, 8]. However, the perioperative risk from cardiovascular intervention has been significantly increased compared to the general cardiac patient population [9], and long-term survival has been relatively low [2, 6]. These poor results have been attributed to a multitude of coexisting noncardiac disorders [1, 10], to the pathologic consequences of the renal disease and dialysis-inclusive infective endocarditis [3] and to advanced cardiac disease [1].

Recent studies show considerable improvement of perioperative and long-term survival in relatively small series of well-selected patients [1, 6, 11]. Particularly, congestive heart failure class IV according to the New York Heart Association (NYHA) [6] and severely reduced left ventricular function (ejection fraction < 30%) [9] have been identified as predictors of early and late mortality. In spite of these promising results regarding short-term and long-term survival little information is available concerning long-term functional status.

The goal of the present retrospective study was a detailed analysis of our experience with cardiac operations in patients with dialysis-dependent renal disease with respect to early mortality and morbidity and with special attention to long-term survival and long-term changes in anginal status and NYHA status.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
This retrospective study consists of 45 consecutive patients with end-stage renal disease undergoing a cardiac procedure in our clinic between November 1989 and September 1994. All patients received either hemodialysis (n = 44) or chronic ambulatory peritoneal dialysis (n = 1) for at least 1 month before operation. The cardiac disease leading to the operation was coronary artery disease (CAD) in 31 patients, and valvular disease in 14 patients. In 2 patients (one out of each group) severe calcification of the aorta was detected after pericardiotomy. Cannulation and operation on the ascending aorta were considered to be too dangerous and installment of cardiopulmonary bypass was rejected. One of these 2 patients suffering from CAD and a symptomatic high-grade internal carotid artery stenosis was assigned to a combined procedure initially, but only a thrombendarterectomy with patch plasty of the internal carotid artery was performed. In the second patient the chest was closed without any definite cardiovascular procedure. Some demographic details of the patients are given in Table 1.

Renal failure was attributed to the following pathologic disorders (n = 45): polycystic disease of the kidney (7 patients), chronic glomerulonephritis (5), vascular renal disease (5), toxic (4), chronic pyelonephritis (4), diabetic nephropathy (3), lithiasis (3), history of nephrectomy due to neoplasm and subsequent nephritis of the contralateral kidney (2), gout nephropathy (1), unknown (8 patients). Three patients had undergone renal transplantation with subsequent failure of the donor kidney.

Renal dialysis
All cardiovascular procedures were done while the patients were on maintenance dialysis. The preoperative duration of dialysis varied widely (Table 1). Even those patients who underwent dialysis therapy for as short as 1 month before cardiovascular operation suffered from end-stage chronic renal disease, which had gradually deteriorated to become dialysis dependent. Only in 1 patient with toxic nephropathy renal function recovered significantly, and dialysis therapy was terminated 3 months after cardiac intervention (aortic valve replacement).

In accordance with end-stage renal disease, all patients had azotemia (prebypass level of blood urea nitrogen, 128 ± 8 mg/dL) and elevated creatinine levels (prebypass plasma creatinine, 7.9 ± 0.4 mg/dL).

The perioperative dialysis program consisted of the following procedures: dialysis the day before operation, hemodialysis during the cardiopulmonary bypass, and resumption of dialysis the first or the second day after operation. Hemodialysis was performed in all patients with the exception of 1 patient who was on chronic ambulatory peritoneal dialysis for 10 years and was treated by peritoneal dialysis pre- and postoperatively.

Operative management
Details concerning operation are given in Tables 4 and 5 . Coronary artery bypass grafting (CABG) was performed using cardiopulmonary bypass and moderate systemic hypothermia. Distal anastomoses were sutured on the fibrillating topically cooled heart during aortic cross-clamping. Proximal vein anastomosis were sutured to the ascending aorta partially excluded by a vascular clamp while the heart was beating and being rewarmed. Cardiac operations containing valvular surgery were performed using cold crystalloid cardioplegia.

Follow-up
Data for long-term follow-up were collected from patients’ medical records, from questionnaires sent to physicians and dialysis centers, and from telephone interviews with patients, relatives, and physicians. The follow-up was accomplished between December 1995 and February 1996. Minimum and maximum follow-up after operation was 16 and 72 months, respectively, with a mean follow-up of 36 months. Long-term follow-up was complete for all 45 consecutive patients.

Statistics
Actuarial analysis of long-term survival and cardiac event-free survival were calculated using the method of Kaplan and Meier. All data are expressed as mean ± standard error of the mean unless otherwise stated.

	Results

Top Abstract Introduction Patients and methods Results Comment References

 
Clinical outcomes
The overall 30-day mortality rate was 4.4% (2 of 45 patients). One death occurred in a 68-year-old patient with three-vessel CAD, a history of two previous myocardial infarctions, unstable angina, and a left ventricular ejection fraction < 40%. After initial uneventful recovery the patient died on the fifth postoperative day of unknown cause (dysrhythmia?, acute myocardial infarction?). The other death occurred in a 64-year-old patient with mixed mitral stenosis and incompetence, tricuspid incompetence and a three-vessel CAD with second degree (out of three) reduction of left ventricular function, NYHA classification III. After operation the patient died of multiorgan failure due to sustained inadequate cardiac output within the second week after operation. One more patient died on the 40th day after operation. This patient suffered from acute multivalvular endocarditis with cerebral emboli and mitral papillary muscle rupture. The patient was operated on an emergency basis, and an aortic valve reconstruction and a mitral valve replacement were performed. Eventually this patient died due to sepsis after colon gangrene and perforation with peritonitis (hospital mortality, 6.7%). The overall morbidity was 24% (11 of 45 patients). Details are shown in Table 6. All patients recovered completely from postoperative complications with the one exception of the above-mentioned patient who died on the 40th day after colon perforation with peritonitis. No patients required reoperation for mediastinal bleeding. For the 42 patients who were alive at the time of hospital discharge, maximal stay on our intensive care unit was 7 days; all patients left our department within 10 days and returned to their nephrologic centers for further convalescence.

View larger version (24K): [in this window] [in a new window]   Fig 1. Actuarial survival after operation for coronary artery disease (n = 30, solid circles) and for valvular disease (n = 13, solid triangles). Minimum follow-up was 16 months. Short and long vertical bars represent either 1 or 2 patients, who were lost to analysis, as they were alive at the time of follow-up.

Five patients received a renal transplantation 32 ± 9 months after cardiac operation, which was a CABG procedure in 4 patients.

Of the 20 patients surviving the CABG procedure, 12 were free from anginal pain after 36 ± 4 months, 6 patients had stable angina and 2 had unstable angina (Fig 2). The 2 patients, who deteriorated from stable to unstable angina, were alive 20 and 52 months after operation. Neither completeness of revascularization nor the use of arterial grafting were predictors of better functional results (not shown). Incomplete revascularization was formally defined as not all major vessels with severe arterial disease (either stenosed or occluded) having received a bypass grafting. Seven of the 8 patients surviving a valvular operation showed improved functional status 35 ± 5 months after operation (Fig 3). Only one 69-year-old patient went from NYHA class II to class III 32 months after aortic valve replacement due to increasing mitral regurgitation.

View larger version (22K): [in this window] [in a new window]   Fig 2. Late postoperative changes of ischemic symptoms after coronary artery bypass grafting in patients suffering from stable angina preoperatively (top) or unstable angina preoperatively (bottom). The numbers of patients are indicated.

View larger version (19K): [in this window] [in a new window]   Fig 3. Late postoperative changes of New York Heart Association (NYHA) functional class after valvular operation. The numbers of patients are indicated.

	Comment

Top Abstract Introduction Patients and methods Results Comment References

 
Patients on maintenance dialysis suffer from a broad spectrum of cardiovascular diseases. Approximately 30% to 50% of deaths in dialysis patients can be attributed to cardiovascular disease [5, 8, 12, 13] compared to less than 15% of deaths in an age-corrected control population [14]. It has been proposed that possibly some of the cardiac disorders might be aggravated by renal disease itself or by comorbid findings [15] associated with end-stage renal disease. For example, coronary heart disease is unusually prevalent in patients with end-stage renal disease, but nevertheless it still remains unclear whether the progress of CAD is accelerated in dialysis patients [10, 16, 17] compared to the general population. Also, valvular calcification may be accelerated in patients with chronic renal failure [7, 18] and septic events with endocarditis may be regarded as typical complication from long-term hemodialysis procedures [3, 6]. Only recently larger series of successful cardiac operations have been published [1, 4–6, 9, 11, 18–20], and reports on long-term results after cardiac intervention are scarce [1–6, 11, 19, 20].

The perioperative risk of cardiac operation has been shown to be considerably increased in patients with maintenance hemodialysis compared to the general cardiac patient population, possibly due to a multitude of comorbid disorders like hypertension and diabetes mellitus, or due to advanced disease. Ko and colleagues [9] summarize the results of 296 cases of cardiopulmonary bypass procedures in dialysis patients in the literature and found an overall mortality of 9%. In series consisting of more than 20 patients the range of perioperative mortality was 3% to 25% (with a mean of 10%). The lethal risk of valvular operation and combined operation (7 deaths in 54 patients; mortality, 13%) was slightly higher than the risk of CABG (20 deaths in 236 patients; mortality, 8%). More recent studies are well in support to these findings; Owen and colleagues [1] observed at CABG in patients with dialysis-dependent renal failure a mortality rate of 9% and Kaul and associates [6] found a mortality of 11% at cardiac operations in patients with end-stage renal disease. The latter investigators state that a subgroup of patients undergoing a reoperation had a considerable higher mortality (29%; 2 of 7 patients), and all perioperative deaths occurred in patients who were in class IV cardiac heart failure preoperatively. Two further studies showed somewhat different results: one of these showed a mortality of 31% (4 of 13 patients) [21], most likely attributable to the mean age of 69 years, which was a decade older than in nearly all other reports (Table 8). The other study consisted of 23 patients undergoing CABG (mean age, 55 years) with no hospital death reported [11]. Our own experience with 2 perioperative deaths in 45 patients undergoing a cardiac operation (mortality, 4.4%) is well in line with the preceding studies. These 2 deaths and a further death in a patient who died on the 40th postoperative day occurred in patients with advanced diseases. This finding puts emphasis on the utmost importance of careful selection of dialysis-dependent patients.

Does cardiac operation improve life quality in patients on long-term dialysis with cardiac disease and what factors might determine long-term functional outcome? Fifteen of 20 patients (75%) with CAD showed pronounced symptomatic improvement still 3 years after CABG compared to the preoperative evaluation, only 2 of 20 patients (10%) showed deterioration. Completeness of revascularization did not seem to be of importance in our series. Furthermore, patients with arterial grafting did not do better in our series than those with complete venous grafting. In fact, 2 of 5 patients (40%) with arterial grafting worsened. However, the low number of patients and the fact that no postoperative angiograms were performed to examine the patency of venous or arterial grafts rules out any further conclusions. Less than complete revascularization has also been addressed by Koyanagi and colleagues [11]. These investigators emphasize that incomplete revascularization is because most patients on chronic hemodialysis are known to have extensive coronary disease. As well as having a large number of lesions in each vessel, such patients show diffuse and calcified lesions and poor distal runoff, obliging to perform less than complete revascularization. All but one long-term survivor improved after valvular or combined cardiac operation and they were in good NYHA state on the average 3 years after the operation (Fig 3). Other long-term results on dialysis patients with valvular operations are missing.

In conclusion, cardiovascular operations can be performed with good short-term and long-term results in patients with renal failure dependent on chronic dialysis, provided a carefully selection of the patients is assured. Patients more than 70 years of age and patients with advanced cardiac diseases and poor ventricular function might be excluded from operation because they do not gain a benefit from cardiovascular operation. Their perioperative risk seems consistently to be increased [9, 21], and the long-term outcome is significantly decreased [6]. But with the exception of these high-risk patients, the life expectancy of dialysis patients undergoing a cardiac operation can be approximated to the life expectancy of the general patient population on maintenance dialysis. Cardiac events can be reliably prevented and valvular or endocarditic lesions can be successfully repaired. Our study demonstrates that in the long-term course anginal pain is being relieved in most patients with coronary artery disease and functional status according to the NYHA classification is improved in patients with valvular and combined diseases. Cardiac operation may be a prerequisite before renal transplantation.

	References

Top Abstract Introduction Patients and methods Results Comment References

 

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