Appraisal and reappraisal of cardiac therapy Edited b y A th r ur C. DeGraff, Alan F. Lyon, and Julian Frieden

Surgical treatment of valvular heart disease

Part Hi. Surgical repair of the stenotic mitrcd valve

George Robinson, M.D.* Seymour Furma.n, -Vl.D.** Lari A. Attai, M.D.“”

Bronx, N. Y.

B efore the development of surgical techniques for the correction of mi-

tral stenosis, *the disease inexorably led to death, usually in the sixth decade of life. The slow, progressive decline in cardiac performance characteristic of mitral ste- nosis was sometimes accelerated by bac- terial endocarditis or arterial embolism. Since 1948, when the first acceptable surgi- cal manipulations of the valve were per- formed, the natural history of mitral ste- nosis has been radically altered. Incapaci- tating symptoms have been relieved and the longevity of surgical survivors in- creased.r Despite an incomplete under- standing of mitral valve pathology and function, and the use of techniques now considered obsolete, there were lasting ben- eficial results in almost half the operated cases.

The problem of early and late deteriora- tion of surgically treated cases had not been foreseen in the early years of closed mitral surgery, although it was apparent to most workers that relief of mitral stenosis was not being achieved with regularity. Thick fibrous commissures, calcified leaflets, and subvalvular stenosis due to fusion, thicken-

ing and shortening of chordae tendineae defied the best efforts of surgeons working in the closed heart. Clinical signs of mitral stenosis often persisted after operation al- though some patients felt improved because of elation upon survival from surgery, or from intensified medical care. Late clinical deterioration was observed in some pa- tients who had good anatomical and physio- logical results at operation.

Knowledge of the surgical anatomy of the mitral valve, appreciation of the re- quirements of adequate commissurotomy, improved closed techniques for enlarging the mitral orifice, and the application of safe, direct-vision, open techniques for the relief of mitral stenosis have enhanced the potential for consistent and prolonged sur- gical relief of mitral stenosis.

Selection of $atients fog mitral valve sw- gevy. Surgical relief of mitral stenosis is advised when progressive symptoms of car- diac insufficiency are associated with evi- dence of physiologically significant mitral valve obstruction. The latter can be demon- strated on physical examination, by elec- trocardiography, by radiographic detection of enlargement of the left atria1 and right

From the Cardiothoracic Surgical Service, Division of Surgery, Montefiore Hospital and Medical Center, Bronx. N. Y *Attending-in-Charge, Cardiac Surgery. **Adjunct Attending, Cardiothoracic Surgen-.

286 American Heart Journal August, 1968 Vol. 76, No. 2, pp. 270-274

Surgical treatment of valvular heart disease 287

ventricular chambers, or by sophisticated laboratory documentation of hemodynamic abnormality.

Surgery is not warranted for asympto- matic mitral stenosis. When progressive dyspnea, fatigue, or congestive heart failure are observed, and there is a consequent withdrawal by the patient from appropriate physical activities, surgery is advised. The level of cardiac performance required for any individual is variable, and conse- quently, surgery is indicated by individual circumstances rather than by an arbitrary standard of performance. Arterial embolism is a compelling indication for surgery al- though the associated clinical disability may be mild. The incidence of recurring emboli is reduced by adequate mitral corn-

missurotomv.Z It is possible to predict the condition of

the valve with accuracy in advance of the operative procedure. The type of repara- tive procedure is usually predictable in advance of surgery, especially with refer- ence to the potential need for valve replace- ment. Predictions are based upon age, sex, purity of the stenosis, basic heart rhythm, heart sounds, and radiographic evidence of valvular calcification. The young female with pure non-calcific stenosis, a good first mitral sound and opening snap, and regular sinus rhythm is likely to have a pliable valve which can be corrected by simple commissurotomy.

Surgery may be deferred with justifica- tion in the minimally incapacitated patient who if brought to surgery would require mitral valve replacement. With the passage of time, such patients will be operated upon

earlier in the course of their disease as im- proved prosthetic mitral valves become available.

Physiological evaluation. There are neither absolute hemodynamic indications nor con- traindications to mitral valve repair. Most patients with mitral stenosis do not require cardiac catheterization prior to surgery. On rare occasions, it may be desirable to confirm the presence of mitral obstruction by laboratory methods when clinical evalu- ation is uncertain. When aortic and tri- cuspid valve lesions are suspected clinically, radiologic and hemodynamic methods can help the surgeon plan an operative pro-

cedure designed to correct the significant organic lesions. The research value of serial hemodynamic studies is also recognized.

Objectives of sul’gery. The surgeon’s task is to eliminate mitral valvular and subvalvu- lar stenosis, remove intracardiac thrombus, avoid thrombotic and calcific emboli, and avoid or repair significant mitral insuf- ficiency.3 The surgeon must fulfill these objectives with safety and regularity. Fail- ure to obtain a good clinical result after mitral surgery implies that the hemody- namic result at the mitral orifice is unsatis- factory. While myocardial disease, multi- valvular involvement, or progressive de- struction of the mital valve by disease may compromise a surgical result, a major cause of disappointment is the failure to achieve the stated objectives of surgery.

Surgical technique. Finger fracture of the stenosed mitral valve commissures was introduced nearly 20 years ago. Various aids to the surgeon’s finger were devised to assist in the accuracy or forcefulness of the manipulation. The ungloved index fin- ger permitted more accurate palpation of the valve, and the exposed fingernail was used as a dissector. Fingertips were en- larged with tape to increase the diameter of the dilating wedge. Thimbles and knives were carried blindly into the heart to cut resistant commissures. In 1959, Logan and Turner? introduced the transventricuiar di- lator, which has since been widely used by surgeons in the United States. This instru- ment is introduced through the apex of the Ieft ventricle and guided into position by a finger in the left atria1 chamber. The stric- tured valve is forcibly divulsed, usually lines of fusion, with the initial opening at the least resistant commissure. Although forcible dilatation can injure valve leaflets and chordae tendineae, the over-all superi- ority of this method over transatrial meth- ods has been generally accepted.

There have been relatively few propo- nents of elective open heart surgery for the routine enlargement of the mitral orifice. Lillehei and associates* were the first to per- form reparative surgery under direct vision in 1956. Later, Nicholas and associates3 and Kay and colleagues4 suggested the superior- ity of this method. Our recent experience with elective open heart surgery for mitral

288 Robinson, Fwman, and d ttai .im. Heurt J. dugust, 1968

stenosis confirms the judgments of these earlier reports. The quality of repair possi- ble on the mitral valve under open condi- tions has proved superior to that possible under closed conditions and the objectives of surgery are more frequently fulfilled.

Open mitral commissurotomy with car- diopulmonary by-pass permits the surgeon to perform an unhurried, visually guided controlled complete mobilization of all valve components. Atria1 thrombus is re- moved when encountered and minor de- grees of mitral insufficiency are easily corrected.

Results

The immediate hemodynamic effects of repair of the mitral valve is the abolition of the diastolic pressure gradient between the left atrium and the left ventricle. Pulmo- nary artery pressure falls slightly. There is neither significant improvement in cardiac output at surgery nor immediately after- ward except for the temporary effect achieved by deliberate expansion of blood volume or by the use of inotropic agents. Continuation of the low cardiac output into the postoperative period is probably re- lated to impaired function of the left ven- tricle, as is indicated by immedi.ate post- operative hemodynamic studies.5

Operative death from closed mitral pro- cedures is 3.4 to 8.5 per cent in some large series that have been reported. An earlier report on elective open repair indicated a mortality rate of 6.5 per cent. Our experi- ence with elective open heart mitral valve repair yielded an operative mortality rate of 1.9 per cent in a consecutive series of 103 patients.” One patient succumbed at 35 days from causes unrelated to surgery for a total hospital mortality rate of 2.9 per cent. Complications following open heart surgery were similar to those encountered after closed surgery, but the incidence of intra- operative arterial emboli was reduced greatly by the ability to control atria1 thrombus when encountered.

Sustained clinical improvement following surgery is noted in approximately 40 to 7.5 per cent of patients submitted to operation by closed techniques. Long-term follow up on patients operated upon by open tech-

niques is not yet available. Superior long- term results may be expected from open techniques of mitral repair if sustained im- provement is related to the completeness and accuracy of the surgery on the valve.

Summary and conclusions

Kearly 20 years of experience with surgi- cal repair of the stenotic mitral valve have demonstrated that it is of value in improving cardiac function and in increasing lon- gevity. Though at times, the benefits are not permanent, many unsatisfactory re- sults can be attributed to incomplete relief of all the obstructing elements of the mitral valve. Improved techniques in closed surgi- cal procedures have yielded acceptable clinical results. Safe cardiopulmonary by- pass permits accurate direct vision repair of the valve under ideal surgical conditions, and it is reasonable to anticipate that a better operation will provide more enduring palliation and greater longevity. Our pres- ent experience indicates an operative mor- tality rate of 1.9 per cent for the open operation. The discovery of a perfect mitral prosthesis, however, would make all con- servative operations on the valve obsolete.

Editors’ Note:

Dr. Robinson presents a convincing case for open repair in all patients with mitral stenosis. Next month, the opposing view will be upheld by Dr. George Reed. In both reports, surgical death has been exceed- ingly low. It should be noted that these patients all had mitral valvotomy. Surgical morbidity and death in patients requiring prosthetic replacement (after an intra- operative decision) has invariably been higher.

REFEREXCES

1. Ellis, L. B., and Harken, 1). E.: Closed val- vuloplasty for mitral stenosis, New England J. Med. 270:643, 1964.

2. Bakoulas, G., and Mullard, K.: Mitral val- votomy and embolism, Thorax 21:43, 1966.

3. Nicholas, H. T., Blanco, G., Morse, D. P., Adam, A., and Baltazar, N.: Open mitral commissurotomy, J.A.M.A. 182:268, 1962.

4. Kay, E. B., Rodrizuez, P., Haghighi, D., Suzuki, A., and Zimmerman, H. A.: Mitral stenosis: Comparative analysis of postopera-

Surgical treatment of valvdar heart disease 289

tive results following the closed and open oper- ative approach, Am. J. Cardiol. 14:139, 1964.

5. Austen, W. G., Corning, H. B., Nforan, J. M., Sanders, C. A., and Scannell, J. G.: Cardiac hemodynamics immediately following mitral valve surgery, J. Thoracic & Cardiovas. Surg. 51:468, 1966.

6. Robinson, G., and Attai, L. A.: Presented at the Fourth Annual Meeting, Society of Tho- racic Surgeons, New Orleans, La., Jan. 31, 1968.

7. Logan, A., and Turner, R.: Surgical treatment of mitral stenosis with particular reference to the transventricular approach with a mechani- cal dilator, Lancet 2:874, 1959.

8. Lillehei. C. W.. Gott. V. L.. De Wall. R. A.. and Varco, k. L. : The surgical treatment of stenotic or regurgitant lesions of the mitral and aortic valves by direct vision utilizing a pump oxyge- nator, J. Thoracic Surg. 35:154, 1958.