and Coronary Artery Surgery George M. Callard, M.D., John B. Flege, Jr., M.D., and Joseph C. Todd, M.D.

Transcription

1 Combined Valvular and Coronary Artery Surgery George M. Callard, M.D., John B. Flege, Jr., M.D., and Joseph C. Todd, M.D. ABSTRACT Between July, 97, and March, 975,45 patients underwent combined valvular and coronary artery operation. valve disease was present in 30 patients, mitral valve disease in 3, aortic and mitral valve disease in, and tricuspid valve disease in. The average age was 57 years. Seventeen patients were in New York Heart Association Functional Class IV. Seventeen patients had had a previous myocardial infarction. Significant coronary artery disease was an unexpected finding at the time of coronary angiography in 4 patients. The average number of grafts inserted was 2.5 per patient. The grafts were placed prior to valve replacement, and periods of myocardial ischemia were kept at a minimum by maintaining coronary perfusion throughout the operation. Operative mortality was 6%; late mortality was So/& Perioperative myocardial infarction occurred in 2 patients. In spite of the marked improvement in operative results following valve operations, myocardial infarction and ischemia continue to be a common cause of early and late mortality and morbidity [ll, 4, 8. The use of coronary angiography at the time of cardiac catheterization for evaluation of valvular heart disease can identify those patients with coexisting coronary artery disease. Direct revascularization by aortocoronary bypass grafting at the time of a valve procedure should decrease the operative risk and may improve the long-time result by reducing the likelihood of subsequent myocardial infarction and symptoms of ischemia. The experience with 45 patients undergoing combined valve operation and aortocoronary bypass grafting demonstrates that the combined procedure can be performed with satisfactory results. From the Christ Hospital, Cincinnati, OH. Presented at the Twenty-second Annual Meeting of the Southern Thoracic Surgical Association, New Orleans, LA, NOV 6-8, 975. Address reprint requests to Dr. Callard, 239 Auburn Ave, Cincinnati, OH Materials and Methods Between July, 97, and March, 975, 29 patients underwent valve replacement or valvuloplasty. All patients over the age of 40 years and any younger patient with symptoms suggesting coronary artery disease were evaluated by coronary angiography at the time of cardiac catheterization. Forty-five patients were found to have significant atherosclerotic coronary artery occlusive disease and underwent aortocoronary bypass grafting with saphenous veins at the time of the valve procedure. The distribution and severity of coronary stenosis is illustrated in Table. Thirty patients had aortic valve replacement, 3 patients underwent mitral valve replacement or mitral valvuloplasty, patient had aortic and mitral valve replacement, and had tricuspid valve replacement. Thirty-five patients were men, and 0 wer'e women. Ages ranged between 34 and 75; the average age was 57 years. Four patients were 70 or older. The patients were classified preoperatively according to the New York Heart Association functional criteria. Seventeen patients were in Functional Class IV, 8 were in Class, and 0 were in Class II. Twenty-eight of the patients had angina pectoris. Seventeen had had a previous myocardial infarction (Table 2). The hemodynamic abnormalities are listed in Table 3. Fifteen patients had predominant aortic stenosis. Peak systolic gradients ranged between 40 and 00 mm Hg. regurgitation was present in 7 patients, while 8 had mixed aortic stenosis and regurgitation. Six patients had rheumatic mitral valve disease. Severe mitral stenosis was present in 5 patients and mitral regurgitation in. Two patients had ruptured chordae tendineae; this resulted from myxomatous degeneration of the mitral valve apparatus in patient and ischemic heart disease in the other. Five patients had papillary muscle dysfunction and had papillary muscle 338

2 339 Callard, Flege, and Todd: Combined Valvular and Coronary Artery Surgery Table. Distribution and Severity of Coronary Artery Disease in 45 Patients Undergoing Combined Valvular and Coronary Artery Operation Valve Replaced & Severity Coronary Artery of Coronary Artery Occlusion L Main LAD Circ. RCA Total occlusion 75-99% 50-74% Total occlusion '/o 50-74% & mitral 75-99%.. and a disposable bubble oxygenator. Ventricular fibrillation was induced, and the left ventncle was decompressed through the right superior pulmonary vein. The saphenous vein-coronary artery anastomosis was then performed. While the anastomosis was being done, the coronary artery was occluded temporarily by compression to control bleeding from the arteriotomy. The aorta was cross-clamped only... 4 when aortic regurgitation was present. In this situation, the aorta was opened and the coro nary arteries were perfused with cannulas inserted in the coronary ostia. Following comple tion of all of the coronary bypass grafts, valve replacement or valvuloplasty was performed An average of 2.5 grafts per patient was per- formed. The number of grafts ranged from a single graft in 0 patients to 5 grafts in2 patients. The aortic valve was replaced in all patients with either a Starr-Edwards (Model 260 and Model 75-99% ) or a Bjork-Shiley prosthesis. valve replacement was performed in 8 patients with a LAD = left anterior descending coronary artery; circ. = Starr-Edwards prosthesis (Model 6320) and in 2 circumflex coronary artery; RCA = right coronary artery. patients with a porcine xenograft. Three mitral rupture, all secondary to ischemic heart disease. The patient with tricuspid valve disease had valvuloplasties were performed. The tricuspid valve was replaced with a porcine xenograft. Ebstein's anomaly with an atrial septa defect and a right-to-left shunt. The operative technique remained standardized. Each portion of the operative procedure was done separately and in sequence. The aortocoronary bypass grafts were always performed prior to the valve replacement. The proximal aortic-saphenous vein anastomosis was done as the initial part of the procedure. Cardiopulmonary bypass was then instituted using hemodilution, mild hypothermia (32" to 34" C), Results Operative and late mortality is presented in Table 4. Five early deaths occurred following aortic valve replacement. Two deaths were due to left ventricular failure and occurred in patients with previous myocardial infarction who were in severe congestive heart failure prior to operation. The 3 remaining deaths were due to uncontrolled bleeding at operation, hemorrhagic pancreatitis occurring 0 days postopera- Table 2. Presence of Angina or Previous Myocardial Infarction in 45 Patients Undergoing Combined Valvular and Coronary Artery Operation Valve Replaced No. of Patients Angina Previous MI & mitral Total (62%) 7 (38%) MI = myocardial infarction.

3 340 The Annals of Thoracic Surgery Vol 22 No 4 October 976 Table 3. Hemodynarnic Abnormalities in 45 Patients with Combined Valvular and Coronary Artery Disease Valve & Type of Disease Stenosis Regurgitation Mixed RHD, stenosis RHD, regurgitation Ruptured chordae Papillary muscle dysfunction Papillary muscle rupture No. of Patients evidence of dysfunction of the prosthetic valve or of failure of the vein grafts at postmortem examination. The third patient died with left heart failure and multiple arrhythmias 5 months following mitral valve replacement for papillary muscle dysfunction. Left ventricular function was markedly impaired prior to operation and failed to improve postoperatively. Myocardial infarction as demonstrated by the appearance of new Q waves on the electrocardiogram postoperatively occurred in only 2 patients. Both patients had had aortic valve replacement and had an uncomplicated recovery following operation despite evidence of a perioperative myocardial infarction. Evidence of myocardial necrosis demonstrated by cardiac enzyme elevation was not obtained on a routine Ebstein s anomaly basis in any of the patients. RHD = rheumatic heart disease. tively, and fungal endocarditis occurring 30 days postoperatively, respectively. There were 2 early deaths following mitral valve replacement. Both occurred in patients in congestive heart failure with papillary muscle dysfunction following myocardial infarction. There were 3 late deaths. Three months following aortic valve replacement, a patient developed thrombocytopenia while receiving quinidine and died following an intracerebral hemorrhage. A second patient with a long history of rheumatic heart disease and congestive failure died year after mitral valve replacement with progression of heart failure. There was no Comment The routine use of coronary angiography in the evaluation of patients with valvular heart disease has demonstrated that a significant number of patients have coexisting coronary artery occlusive disease. The reported incidence of coronary occlusive disease in patients with valvular heart disease varies between 7 and 48% [7, 3. A number of reports indicate that patients with combined valvular and coronary artery disease always have angina [3,6]; they conclude that the increased workload imposed by the valvular lesion produces an increased myocardial oxygen demand and precipitates symptoms of myocardial ischemia. A definite history of angina, however, was present in only 28 (62%) of our Table 4. Mortality and Incidence of Postoperative Infarction in 45 Patients Undergoing Combined Valvular and Coronary Artery Operation Postoperative Late Type of No. of Deaths Deaths Operation Patients No. % No. % AVR, ACBPG 30 5 MVR, ACBPG 3 2 AVR, MVR, ACBPG 0 TVR, ACBPG Total AVR = aortic valve replacement; MVR = mitral valve replacement; TVR = tricuspid valve replacement; ACBPG = aortocoronary bypass graft.

4 34 Callard, Flege, and Todd: Combined Valvular and Coronary Artery Surgery patients (see Table 2). In 4 patients (3%), significant coronary artery disease was an unexpected finding at the time of coronary angiography. This finding supports the policy of performing coronary angiography routinely during the evaluation of valvular heart disease in spite of the absence of angina. Various reports have demonstrated that valve replacement can be combined successfully with coronary bypass grafting [2, 5, 5-7. While some reports have indicated that the operative risk is considerably higher than the risk with either isolated valve replacement or coronary bypass grafting, other reports have demonstrated that the operative risk for the combined operation is essentially the same as that for either operation alone [4, 8. In our series the operative mortality for the combined operation (6%) exceeds the current risk of isolated valve replacement or bypass grafting alone [l, 0,2. Whether the combined operation has a significant effect in decreasing operative and late mortality cannot be determined without having the opportunity to compare these patients to a group of patients with comparable coronary artery disease undergoing valve replacement alone. Only 2 of the operative deaths in the patients undergoing aortic valve replacement were due to myocardial factors. Both of these patients had had previous myocardial infarctions and had diffuse three-vessel coronary artery disease demonstrated angiographically. One of the patients had severe aortic stenosis with an 80 mm Hg gradient and evidence at postmortem examination of a recent myocardial infarction. The other patient had severe aortic regurgitation, three-vessel coronary disease, and an aneurysm of the aortic arch. Both were in Functional Class V. The remaining 3 deaths following aortic valve replacement were due to either technical or noncardiac factors. The 2 deaths occurring after mitral valve replacement were due to myocardial failure. Both patients had had previous myocardial infarctions and had severe mitral regurgitation due to papillary muscle dysfunction. Both had severe three-vessel coronary disease and were in Functional Class IV. Gratifying results were obtained in the remaining patients, all of whom had severe valvular disease and significant coronary artery occlusive disease. Throughout our experience great emphasis has been placed on maintaining continuous and adequate coronary perfusion. Hypothermic anoxic cardiac arrest was not employed. When aortic cross-clamping was necessary, the aorta was opened and the coronary arteries were perfused through the coronary ostia. A dry field was maintained while the vein-coronary artery anastomosis was performed by occluding the artery immediately proximal and distal to the arteriotomy. Cross-clamping of the aorta was rarely employed. Though very satisfactory results have been reported with the use of hypothermic anoxic arrest [9], we believe that the maintenance of coronary perfusion with brief or no interruption is vitally important in the prevention of myocardial necrosis intraoperatively. By performing the aortocoronary bypass graft as the initial part of the operation, coronary perfusion is improved early in the operation and the period of ischemia is shortened. Of equal importance is the policy of grafting all major coronary vessels with significant obstruction. It has been our policy to graft any vessel with greater than 50% obstruction. An average of 2.5 grafts per patient was performed. It has not been demonstrated that the increase in operative time required for multiple grafts has impaired the operative results. It is accepted that patients undergoing valve replacement who have coexisting coronary artery disease have a significantly higher operative mortality than patients free from coronary disease. It remains uncertain whether the addition of coronary artery bypass grafting in these patients actually decreases the operative mortality and improves long-term results. We believe, however, that coronary bypass grafting can be performed in conjunction with valve replacement without a significant increase in operative risk. By improving myocardial perfusion at the time of the valve operation, coronary bypass grafting may lower operative risk and improve late results in formerly high-risk patients. Severe coronary artery disease should not be a contraindication to valve operation. References. Allen WB, Karp RB, Kouchoukos, NT: valve replacement: Starr-Edwards cloth-covered composite-seat prosthesis. Arch Surg 09:642, 974

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