Surgical treatment of ischaemic valve disease

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Cord~o~‘uvculur- Surjier~ Vol 4, No 2. pp. 246 24Y, lYY6 0 1996 The lnternatmnal Society for Cardiovascular Surgery Published hy Elxvier Science Ltd. Printed m Great Bruin 0967-2109196 $15.00 + 0 00

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Surgicaltreatment of ischaemicvalvedisease M. Hachida, M. Endo, Y. Bonkohara, M. Nonoyama, H. Nishida, N. Hanayama, A. Hashimoto and H. Koyanagi Department of Cardiovascular Surgery. The Heart inst&ute of Japan, Tokyo Women 3 Medical College, 8-l. Kawada-cho, Shirjbku, Tokyo 162, Japan

Mitral valve regurgitation secondaryto ischaemicheart diseasecarries a significant mortality even after open-heart surgery. In this study, 21 patients with mitral regurgitation associated with ischaemic heart diseasewere evaluated with respect to valvular pathology. Pathological examination of the mitral valverevealedchorda elongation or rupture in sevenpatients (group I), papillary muscle dysfunction in 10 (group 2). and papillary muscle rupture in four (group 3). Significant preoperative characteristics in each group were subacute haemodynamic deterioration in group 1, chronic severeleft ventricular failure in group 2, and a high incidence of acute renal failure associatedwith haemodynamicshock in group 3. Mitral valveplasty was performed in six patients and mitral valvereplacement, using the St Jude Medicalvalve,in 1S. Fourteen patients underwent mitral valve surgery combined with coronary artery bypass grafting. Mitral plasty was applied to the patients with low left ventricular function with mean(s.d.) fraction shortening of 19.2(6.2)% compared with 30.2(8.4)% in patients with mitral valve replacement. There were no operative deaths. Of four late deaths, two in group 1 resulted from infection and myocardial infarction, respectively, and one in group 2 resulted from arrhythmia. One patient in group 3 died from renal failure. It is suggested that incorporation of

these therapeutic concepts may lead to satisfactory results in the surgical treatment of ischaemic mitral regurgitation.

Keywords: coronary valve disease,coronary artery bypassgrafting, ischaemicvalve disease,papillary muscle dysfunction, mitral plasty. mitral valve replacement Although ischaemic mitral regurgitation is an uncommon manifestation of coronary disease, its therapeutic management is difficult, and long-term results are less than ideall. In 1978, Radford et al.’ first reported that operative survival for ischaemic valve diseasecombined with a poor ejection fraction was only 38%. In 1984, Pinson and colleagues3 demonstated a slight improvement in operative survival, up to 62%. Most recently, Rankin et aL4p5 reported that operative survival was 80% in elective operation. However, 3-year survival is still unsatisfactory; Feuvre and co-workers6 reported in 1992 that only 45.5% survived. The aim of the present study was to evaluate the current surgical results for ischaemic valve disease at the authors’ institute and to propose a therapeutic concept which will improve the poor prognosis of this condition. Correspondence

246

to: Dr M. Hachida

Patientsandmethods Patients The patient population was divided into three groups with respect to the type of pathological findings of the mitral valve. In total, 21 patients with mitral regurgitation associated with coronary artery diseaseunderwent surgical treatment. All had significant coronary artery disease and akinesis of the left ventricular posterior wall. Mitral regurgitation appeared after coronary artery disease was diagnosed in all patients. Previous myocardial infarction was seen in 20 of 21 patients (95%). The pathology of the valve lesion found at operation revealed chorda elongation or rupture in seven (group l), papillary muscle dysfunction in 10 (group 2), and papillary muscle rupture in four (group 3). The preoperative characteristics of the patients in each group were evaluated with age, New York Heart CARDlOVASCULAR SURGERY APRIL 1996 VOL 4 NO 2

Surgery for ischaemicvalvedr&ase:M. Hachidaet al.

Association (NYHA) functional classification, cardiogenit shock, renal failure and distribution of coronary diseaseas indicators (Table 1). The mean age of group 3 patients was significantly higher than that of the other groups. The percentage of patients with preoperative NYHA class above grade III was 59.1% in group 1, 30% in group 2 and 100% in group 3. Incidence of preoperative cardiogenic shock was 14.2%, 0%, and 100% in groups l-3 respectively. The incidence of renal failure due to congestive heart failure, indicated by a creatinine clearance of < 40 mYmin, was 28% in group 1, 0% in group 2 and 75 % in group 3 (Table 1). Hence, haemodynamic deterioration was significantly greater in groups 1 and 3 in association with a higher incidence of renal failure and circulatory collapse. In contrast, severe chronic ventricular failure was seen in group 2. The distribution of coronary lesions in group 1 was 100% in the left descending artery, 66.7% in the left circumflex artery, and 66.7% in the right coronary artery. Respective values in group 2 were SO%, 70% and 80% and in group 3, 35%, 100% and 25% (Table 1) There was no significant deviation in the distribution of the Table 1

coronary artery lesions in each group. Mitral valve regurgitation from the posteriomedial commissure detected by echocardiography was 71.4% in group 1, 80% in group 2 and 100% in group 3. The lesian was localized significantly at the posteromedial commissure in each patient group. The grade of mitral regurgitation was either moderate (50%) or severe (SO%) in group 1 and moderate (88.8%) or severe (12%) in group 2. All patients in group 3 showed severe mitral regurgitation. Using thallium scintigraphy, akinesis of the posterior wall was shown to be 80% in group 1, 87.5% in group 2 and 100% in group 3. Operative procedure

Mitral valve plasty was performed nn six patients whereas valve replacement, using the St Jude Medical valve (Getz, Aoyama, Tokyo, Japan), was performed in 15. The decision whether to perform mitral valve plasty or replacement was made according to the valve pathology at the time of operation. Mitral valve plasty was not performed in patients with extensive mitral

Preoperative patient clinical characteristics

No. of patients Mean (sd.) age (years) NYHA classification (ill or IV) Cardiogenic shock Renal failure Coronary lesion Left descending artery Left circumflex artery Right coronary artery

Group 1 (Torn chorda)

Group 2 (Papillary muscle dysfunction)

Grou;; 3 iPapillary muscle rupture)

62.: (6.4) 4 (59.1) 1 (14.2)

10 59.2 3 0 0

4 7‘4.3 4 4 3

2 (28)

(9.3) (30) (0) (0)

8 (80) 7 (70)

6 (iOO)* 4 (66.7)* 4 (66.7)*

-7.8) ; I SO! j 100) ,751

1 !??S) 4 Itoo, 1 f,Ej

8 (80)

*n = 6; NYHA. New York Heart Association. Values in parentheses are percentages

Table i

Operative procedures Group 1 (Torn chorda)

Mitral regurgitation lesion Anterolateral Middle Posteromedial Operative procedure Mitral valve replacement Mitral valve plasty Coronary artery bypass grafting Single Double Triple Intra-aortic balloon pump used Mean (sd.) postoperative catecholamine dose (pg)

Group 2 (Papillary muscle dysfunction)

Group 3 (Papillary muscle rupture)

1 5

a

6

5 s

3 2 1 2 10.2

(42.8) (28.5) (14.2) (28.5) (3.0)

2 (20) 0 (0) 5 (50)

6 (60)

11.7 (5.5)

Values in parentheses are percentages

CARDIOVASCULAR SURGERY AF’RIL 1996 VOL 4 NO 2

247

Surgery for ischaemic valve disease: M. Hachda et al.

valve prolapse. However, in order to shorten the ischaemic time during surgery and preserve the mitral apparatus for postoperative left ventricular function, mitral valve plasty was applied to the patients with low ventricular function, in whom fraction shortening was < 25% and preoperative diameter of the left ventricle > 60mm. Fourteen patients underwent mitral valve surgery combined with coronary artery bypass grafting. The numbers of bypass grafts were single (42.8%), double (28.5%) and triple (14.2%) in group 1, single (ZOO/,), double (0%) and triple (50%) in group 2, and single (25%) in group 3. Thus, the number of coronary grafts was significantly increased in groups 1 and 2 (Table 2). Statistical analysis The characteristics of the patient groups were compared using Fisher’s exact test. To examine differences in hospital survival, late survival, preoperative status and other clinical values in each group, x tests were used for discrete values and the Wilcoxon rank sum test for continuous values. Summary data are presented as mean(s.d.). The two groups of patients were compared by independent t-tests and by analysis of variance, when indicated.

Results No operative death (defined as any death that occurred within 30 days after the operation) was seen in the present series. Long-term actuarial survival (5.76 years) was 71.4% in group 1, 90% in group 2 and 75% in group 3. The causes of death were myocardial infarction (3 years) and pneumonia (3 months) in group 1, arrhythmia (6 months) in group 2 and renal failure (3 months) in group 3. The patency of the coronary bypass graft was 85% in the saphenous vein graft and 100% in the internal thoracic artery. There was no relationship between occlusion of the coronary artery graft and death. The number of bypass grafts, when compared between those patients surviving and those dying was 1.25 per patient among survivors and 2.76 per patient in those dying (P < 0.05). These data suggest that severe associated coronary artery disease is a significant risk factor for long-term survival. Comparison of surgical results between mitral valve replacement and mitral valve plasty in group 2 (Table 3) showed that the mean(s.d.) preoperative diameter of the left ventricle was 58.1(6.1) mm in the replacement group and 65(3.7) mm in the plasty group (P
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‘able 3 Comparison of postoperative data after mitral valve plasty or valve replacement in group 2 patients

No. with three-vessel disease Mitral regurgitation lesion Anterolateral Posterolateral Mean (s.d.) catecholamine dose (Fg) Intra-aortic balloon pump used Mean (s.d.) cardiac index Preoperative Postoperative Mean (s.d.) fraction shortening (%) Preoperative Postoperative Operative survival (%) Long-term survival (46)

Mitral valve @asty

Mitral valve replacement

5 (100)

1 (20)

1 4 13.3 (4.7) 4 (80)

0 5 11.25 (5.4) 2 (40)

2.89 (0.64) 3.2 (0.91) 19 (6) 14 (8) 100 80

2.46 (0.68) 2.64 (0.69) 30 (8) 24 (4) 100 100

Values in parentheses are percentages

per m2 in the mitral valve plasty group before operation, and 2.64(0.69) and 3.2(0.91) Umin per m2 respectively after operation. Cardiac index was significantly improved after operation in both groups, though no statistical difference was seen between the two groups pre- and postoperatively. Fraction shortening was 30(8)% in the mitral valve replacement group and 19(6)% in the mitral valve plasty group before operation, and 24.6(4.3)% and 24.3(8.6)% in these groups respectively after operation, though there was no statistical inter-group difference. However, no further deterioration in fraction shortening was seen in the mitral valve plasty group, which may have contributed to the satisfactory short- and long-term survival rate in group 2. In the long term, one patient in the mitral valve plasty group died as a result of arrhythmia. The remaining patients of both groups survived long term. Intra-aortic balloon pumping was required by 28.5% of patients in group 1, 60% in group 2 and 75% in group 3. The catecholamine dose used postoperatively was 10.2(3.0) yg in group 1,11.7(5.5) ug in group 2 and 13.5(5.O)ug in group 3 (P = n.s.). In group 3, two patients with postoperative renal failure were treated with haemodialysis.

Discussion The clinical imporance of ischaemic valve disease should increase within the next few years. The combination of coronary artery bypass grafting with mitral valve replacement has been associated with an operative mortality of 3 to 48%. Patients with ischaemic mitral regurgitation who require mitral valve correction and coronary bypass grafting show a higher operative mortality than those who require mitral valve replacement or repair’. Recently, Rankin et al.’ reported that

CARDIOVASCULAR SURGERY APRIL 1996 VOL 4 NO 2

Surgery for ischaemk valve diseaser M. Hachda et al

operative survival was 80% in elective surgery and 50% in emergency surgery for ischaemic valve disease. He and colleaguess demonstrated that probability of survival of the valve operation combined with coronary bypass grafting was 91.9%, 89.9%, 78% and 49.9% at 1, 2, 5 and 10 years postoperatively, respectively. The cause of mitral valve disease and the severity of mitral regurgitation were not related to the hospital mortality or long-term survivals. In the present study, patients with ischaemia-related valve disease were classified with respect to the valve pathology of mitral regurgitation, and the relationship between the patients’ characteristics and valve pathology was evaluated in each group. In group 1, subacute haemodynamic deterioration frequently occurred due to severe mitral regurgitation. Mitral valve replacement combined with coronary bypass grafting was performed in 85.7% of these patients. In this group, the pathological findings of the mitral valve were mainly chordal rupture due to ischaemic deterioration. With regard to mitral repair in these patients, mitral valve plasty using both McGoon’s method’ and Kay’s procedure’” was performed in one patient. However, the remaining patients underwent mitral valve replacement, becausethe preoperative left ventricular diameter was 5.8(0.3) mm, and the diameter of the valve annulus was not enlarged. Therefore, mitral valve replacement was first selected for repair in this group of patients. The postoperative course in this group was fairly good but the risk of myocardial infarction might be high in the long term because of the rapid progression of coronary artery disease. In group 2, chronic heart failure with an enlarged left ventricle and a poor ejection fraction were prominent characteristics. Since preoperative left ventricular diameter was increased to 64(0.4) mm and mitral regurgitation was localized at the posteromedial commissure in 80% of cases, Kay’s procedure was applied at the posteromedial commissure in 50% of patients to shorten ischaemic time and preserve left ventricular function while leaving the mitral apparatus. Kay et ~1.” suggestedthat repair of the mitral apparatus rather than valve replacement was associated with better long- and short-term survival. Rankin and co-workers4 demonstrated an improvement of operative survival after valve repair as compared with valve replacement. However, although postoperative cardiac function was improved in both mitral valve plasty and valve replacement in the present series, no further deterioration in fraction shortening was seen after mitral plasty in group 2, which may have contributed to satisfactory operative survival. Gerbode et al.” reported that operative survival of papillary muscle rupture was 48%. In the present series,

CARDIOVASCULAR SURGERY APRIL 1996 VOL 4 NO 2

three of four patients with papillary musde rupture survived after operation. The finding of a murmur from mitral regurgitation in the immediate postinfarction period and immediate haemo$namic impairment were common in group 3 patients . The authors’ principal therapeutic concept for these patients was immediate surgery without an invasive examination such as angiography. When echocardiography suggested severe mitral valve regurgitation in patients with clinical signs of acute myocardial infarction, an emergency operation should be considered. In most of the patients in group 3 no other coronary lesions needed to be revascularized. Also, these patients showed a high incidence of preoperative renal failure. Therefore, immediate surgical intervention was recommended for better surgical results. It was concluded that incorporation of these therapeutic concepts led to satisfactory results in the surgical treatment of ischaemic mitral regurgitation.

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Merin G, Giuhani ER, Pluth JR, Wallace RB, Danielson GK. Surgery for mitral valve incompetence after myocardiai infarction. Am J Cardiol 1973; 32: 322-4. Radford MJ, Johnson RA, Buckley MJ, Daggetc WM, Leiback RC, Gold HK. Survival following mitral v&e replacement for mitral regurgitation due to coronary artery disease. ] Chdiovasc Surg (Torino) 1978; 2: 39-47. Pinson CN, Cobanoghe A, Metzdorff MT, Grunkemeier GL, Kay PH, Starr A. Late surgical results for ischemic mitral regurgitation. J Thorac Cardiouasc Surg 19184; X8: 66.3-72. Rankin JS, Feneley Ml’, Hickey SMJ et al. A clinical comparison of mitral valve repair versus valve replacement in ischemic regurgitation. / Tborac Cardiovasc Surg’198X; 95: 165-77. Rankin JS, Hickey SMJ, Smith LR er u!. lschemic mitral regurgitation. Circulation 1989: 79(suppt. l): I1 16-21. Fe&e CL, Metzger JP, Lachurie ML,-Georges JL, Baubion N, Vacheron A. Treatment of severe mitral regurgitation caused by ischemic papillary muscle dysfunction: indications for coronary angiography. Am Heart / 1992; 123: 860-S. Connolly MW, Gelbfish JS, Jacowitz IJ et ai. Surgical results for mitral regurgitation from coronary disease. ,f Tborar C&iouasc Surg 1986; 91: 379-88. He GW, Hughes CF, McCaughan FR ZT ni. Mitral valve replacement combined with coronary artery operation: determrnants of early and late results. Ann TJ7nro; ?;ur~ ._ 1991: 51: 916-23. McGoon DC. Repair of mitral insufficiency due to ruptured chordae tendinae. J Thorac Cardiovdsc Swg 1960; 39: 35742. Kay GL, Kay JH, Zubiate P, Yokoyama T, Mendez M. Mitrai valve repair for mitral regurgitation secondary to coronary arterv disease. Circulation 1986; 74: l-88. Gerbode FL, Hetzer R, Krebber Hj. Surgical management of papillary muscle rupture due to myocardial infarction. World / Surg 1978; 2: 791-6. Nunley DL, Starr A. Papillary muscle rupture complicating acute myocardial infarction. Am J Swg 1983; 145: 574-T

Paper accepted 7 October 1994

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