TUESDAY AFTERNOON, May 8, 1984

2:00 p.m. Scientific Session - Grand Ballroom - Third Floor

22. Timing of Coronary Revascularization Following Acute Myocardial Infarction: Early and Late Results in Patients Revascularized Within Seven Weeks

MARK S. HOCHBERG*, VICTOR PARSONNET,

ISAAC GIELCHINSKY, S. MANSOOR HUSSAIN*

DANIEL A. FISCH* and JOHN C. NORMAN

Newark, New Jersey

Complications of acute myocardial infarction (post-infarction angina and cardiogenic shock) usually require early angiography. If significant coronary artery disease is demonstrated, the precise timing of myocardial revascularization may be of critical importance.

From 1978 through 1982,179 patients with documented myocardial infarction underwent early angiography and operation within seven weeks. The male:female ratio was 140:39; average age was 58 ± 1.8 (SEM); and ejection fraction (EF) averaged 41 ± 3%. Forty-eight (27%) patients required pre-operative intra-aortic balloon (IABP) support, and an additional eight (5%) required it to be separated from cardiopulmonary bypass. An average of 2.9 ± 0.2 vessels were bypassed. Hospital mortality for these 179 patients was 17%. However, when mortality rates were categorized according to the post-infarction week in which operation was performed, hospital mortality ranged from 56% for those patients operated upon within one week of infarction to 5% for those patients operated upon seven weeks following infarction. Of those patients operated upon within the first week following infarction, 25% were in cardiogenic shock and 63% required pre-operative IABP. Clearly the most critically ill patients were operated upon during the early post-infarction period.

However, there was a marked difference in survival when patients in each of the seven weekly groups were classified according to EF. All patients with EF ≥ 50% (53 patients) operated upon at any time following infarction survived their hospital course with only one late death. Conversely, of the 126 patients with EF < 50% operated upon during this seven-week interval, there were 32 (25%) hospital deaths and five (4%) late deaths. The difference in early and late survival of patients operated upon with EF ≥ 50% compared to patients with EF < 50% is highly significant (p<.001).

We conclude that myocardial revascularization is safe at any time following myocardial infarction for those individuals with EF ≥ 50%.

*By Invitation

23. Observations on 100 Patients with Continuous Intraoperative Monitoring of Myocardial pH: The Adverse Effects of Reperfusion and Ventricular Fibrillation

SHUKRIF. KHURI*, WILLIAM A. MARSTON*,

MIGUEL JOSA*, NINA S. BRAUNWALD,

ANN C. CAVANAUGH* and ERNEST M. BARSAMIAN

West Roxbury, Massachusetts

The first continuous MpH measurements in man were performed in 100 patients undergoing cardiac surgery with cold K + cardioplegia. Both MpH and the adjacent myocardial temperature (MT) were recorded from the mid and inner layers of the anterior left ventricular wall. MpH and MT data following a single period of aortic clamping (AC) were analyzed to characterize the metabolic correlate of reperfusion and its determinants. MpH at the end of AC (MpH_ac) averaged 6.94 ± 0.04 (Mean ± SEM). Following reflow it fell and reached a nadir (MpH_r) of 6.64 ± 0.03 (P<0.001) in 11.0 ± 0.69 minutes; after that it rose gradually to reach normal levels at discontinuation of cardiopulmonary bypass. MpH_r reached significantly lower levels (6.5 ± 0.07) in the patients (32%) whose MpH_ac was below 6.8 (Group I) than in the patients (68%) whose MpH_ac was above 6.8 (6.78 ± 0.03) (Group II). As shown in the Table, in Group I rapid rewarming (MT above 32 °C at 15 minutes of reflow) caused a significant drop in MpH whereas slow rewarming (MT<30° at 15 minutes) seemed to reduce reperfusion acidosis. In Group II, MpH_r was significantly higher than Group I (P<0.001) and rapid rewarming did not affect MpH more adversely than slow rewarming.

Defibrillation effected a significant rise in MpH in both groups. This rise was significantly more in Group I (0.22 ± 0.03 pH units) than in Group II (0.13 ± 0.02 pH units, P<0.001). Within a narrow range, perfusion pressure did not seem to relate to reperfusion acidosis. It is concluded that the metabolic correlate of reperfusion is a fall in myocardial pH which is determined primarily by the extent of the ischemic damage incurred during the period of AC. When this degree of ischemia is significant (MpH below 6.8), reperfusion acidosis can be significantly reduced by slow rewarming and prompt defibrillation. This study also underscores the value of continuous metabolic monitoring as a new adjunct in the continuing quest for optimal myocardial preservation.

*By Invitation

24. Indications for Ultrafiltration in the Cardiac Surgical Patient

DONALD J. MAGILLIGAN, JR.

Detroit, Michigan

Ultrafiltration is the removal of water and plasma concentration of electrolytes from blood by convective transport across a semi-permeable membrane. We have used Ultrafiltration in 48 cardiac surgical patients and from this experience have evolved indications for its use. Thirty-three of the 48 patients had the ultrafilter inserted in the cardiopulmonary bypass (CPB) circuit at the start of surgery since they had evidence of excess body water preoperatively. The amount of ultrafiltrate removed ranged from 1000 to 6600 ml. and averaged 2728 ml. resulting in an average intraoperative fluid balance of - 638 ml. and an average intraoperative weight gain of 1.9 kg. Eleven of these 33 patients had pre and postop measurement of extravascular lung water (EVLW) by the thermal-dye technique. The postop EVLW (823 ml.) was significantly lower than the preop EVLW (1119 ml.) (p<.05). Thirteen of the 48 patients had the institution of Ultrafiltration after bypass had begun because of a long perfusion and/or excessive pump reservoir volume and/or low hematocrit (Hct). The ultrafilter was easily interposed in the recirculation line during bypass in these patients and resulted in a mean Ultrafiltration volume of 1619 ml. and an average fluid balance of +595 ml. One of the 48 patients with severe CHF, sepsis, respiratory failure and nutritional depletion had Ultrafiltration preoperatively. After Ultrafiltration for 4 days which allowed an intake of 3000 k/cal/ day with a nitrogen balance of +3.2 g/day and without weight gain the patient underwent successful MVR and CABG. One patient returned to the hospital after AYR with no improvement in CHF and resistant to maximal diuretic therapy. Ultrafiltration was instituted through an AV dialysis shunt with a 7.4 kg. weight loss in 7 days and improvement in radionucleide ejection fraction from 37 to 60 percent.

Ultrafiltration is indicated: 1. Intraoperatively during CPB: A) in the patient who shows clinical, radiographic or EVLW evidence of excess body water preoperatively. B) when pump reservoir volumes are excessive. C) when pump volumes are high and the Hct is < 18. Ultrafiltration can be considered: 2. Preoperatively or 3, Postoperatively when a patient needs large fluid volumes for nutritional support or in the fluid overloaded diuretic resistant patient. Our studies showing no increase in EVLW during CPB in the normovolemic patient suggest that the routine use of Ultrafiltration during CPB is not indicated.

*By Invitation

25. A Clinical Trial of Blood and Crystalloid Cardioplegia

STEPHEN S. FREMES*, RICHARD D. WEISEL,

DONALD A.G. MICKLE*, GEORGE T. CHRISTAKIS*,

JOAN IVANOV* and RONALD J. BAIRD

Toronto, Ontario

Although experimental studies suggest that blood cardioplegia (BCP) provides better myocardial protection than crystalloid cardioplegia (CCP), clinical studies remain inconclusive. Eighty-two patients undergoing elective coronary bypass surgery were randomized to receive either blood or crystalloid cardioplegia. Ischemic injury, as defined by the highest postoperative CK-MB was significantly less with BCP (BCP: 27.4 ± 12.7; CCP: 36.7 ± 17.6 U/L, X ± SD, p<0.05). Forty-four patients (BCP: 22; CCP: 22) had more sensitive measurements to assess the metabolic response to aortic occlusion and to compare the metabolic and functional recovery from surgery. Coronary sinus blood flow (CSBF) was calculated by the continuous thermodilution technique and was significantly lower after cross-clamp removal with BCP (BCP: 132 ± 71; CCP: 228 ± 125 mL/min, p<0.01). indicating less reactive hyperemia. Cardiac extraction of lactate was significantly greater with BCP during cardioplegia (BCP: -0.4 ± 0.9; CCP: -1.0 ± 0.7 mmol/L, p<0.01) and immediately after aortic declamping (BCP: -0.1 ± 0.4; CCP: -0.7 ± 0.8 mmol/L, p<0.01). The left ventricle was biopsied prior to aortic occlusion (PRE), immediately after cross-clamp relase (POST) and 30 minutes after reperfusion (LATE). Adenosine triphosphate did not change with BCP (PRE: 16.0 ± 5.7; POST: 15.0 ± 4.9; LATE: 14.4 ± 9.7 mmol/kg dried weight), but decreased significantly with CCP (PRE: 19.9 ± 8.6; POST: 14.1 ± 7.7; LATE: 11.6 ± 3.6 mmol/kg, p<0.01 by analysis of variance, ANOVA). Thermodilution cardiac output measurements permitted calculation of stroke work index (SWI), and nuclear ventriculograms permitted calculation of left ventricular and diastolic volume index (EDVI) and end systolic volume index (ESVI). Myocardial performance (the SWI-EDVI relation) and systolic elastance (the systolic blood pressure -ESVI relation) were significantly better with BCP (p<0.01 by ANOVA), although compliance (the left atrial pressure - EDVI) was similar.

Blood cardioplegia reduced ischemic injury, decreased anaerobic metabolism and permitted better functional recovery. Blood cardioplegia provides superior protection for elective coronary bypass surgery, and may improve the results of surgery in unstable or other high-risk patients.

3:15 p.m. Intermission - Visit Exhibits - Second Floor

Complimentary Coffee

*By Invitation

4:00 p.m. Scientific Session - Grand Ballroom - Third Floor

26. Dysphagia Complicating Hiatal Hernia Repair

ROBERT D. HENDERSON

Toronto, Ontario

Following surgical management of reflux dysphagia may be a continuing or added problem. Radiology alone may not diagnose the problem and only by careful evaluation can a cause be found. In a series of 208 patients treated surgically for a recurrent hiatal hernia, 34 (16.3%) presented with dominant dysphagia. Prior to their original operation 29 had been correctly diagnosed as reflux, however 5 were incorrectly diagnosed (4 D.E.S. and 1 achalasia) and treated by myotomy and hernia repair. The original operation was Nissen (14): Total fundoplication gastroplasty (T.F.G.) (3): Belsey (7): partial fundoplication gastroplasty (P.F.G.) (4): myotomy (5) and unnamed hernia repair (1).

Evaluation by history indicated that dysphagia resulted from the operation (17) and preceeded but was worsened by surgery (17). Radiology showed reflux, recurrent hernias, diverticulae or stasis in 14 (41.2%), however more importantly 20 patients were called normal. When solids were added to barium, obstruction was demonstrated in all patients. Positive manometric and pH findings of reflux, hernia recurrence, intact HPZ with myotomy, increased wrap length and scleroderma were present in 23 (68%). Endoscopic stasis, reflux, elceration or stricture were present in 17 (51.5%).

The etiology of dysphagia was diagnosed in all patients - reflux stricture (9); tight or long Nissen (15); muscle injury (3) inappropriate myotomy with reflux (3); myotomy with over competent repair (2) and early Nissen intussusception (2).

Surgical correction was by T.F.G. (32); Nissen (1) and colon interposition (1). In 4 the myotomy was closed. Complete follow-up averages 3.9 years. There is 1 anatomic recurrence, 28 are asymptomatic and 5 are much improved but have minor persistant dysphagia. Only by complete investigation can the cause of the dysphagia be recognized and treated.

*By Invitation

27. Surgery for Esophageal Achalasia: Results of Esophagomyotomy Without an Antireflux Operation

F. HENRY ELLIS, JR., ROBERT E. CROZIER*

and ELTON WATKINS, JR.

Burlington, Massachusetts

Current widespread enthusiasm for combining an antireflux procedure with esophagomyotomy for esophageal achalasia is, we believe, not only predicated on the incorrect assumption that reflux is common after esophagomyotomy but is a potentially hazardous undertaking when performed in the setting of an aperistaltic esophagus. These concerns prompted us to review our results after esophagomyotomy alone.

Between January 1970 and July 1983, 109 patients with esophageal achalasia underwent esophagomyotomy at the Lahey Clinic. Twenty-nine patients had been treated on one or more occasions by forceful dilation and seventeen had been operated on before. Esophagomyotomy was performed through the left chest by a technique to be described in which the myotomy is limited for the most part to the distal esophagus. No patients died during hospitalization. Eleven (10%) experienced postoperative complications only one of which was significant. Results are based on follow-up studies of 88 patients operated on 1 - 13.5 years ago (average follow-up 6.75 yrs.). Six patients were lost to follow-up and 15 were operated on less than a year ago. Eighty patients (91%) were improved by surgery. The improvement rate was 94% for those undergoing a primary operation and 86% for those undergoing reoperation. Only 3 of the 8 poor results were due to reflux esophagitis and they are satisfactorily managed medically.

Multiple regression and discriminant analysis of such risk factors as age, sex, duration of symptoms, stage of disease, prior operation, or dilations revealed that only prior operation correlated significantly with poor results (p = 0.0002). Because of the high success rate of a limited esophagomyotomy and the low incidence of significant reflux symptoms after its use, we recommend that it be performed without an associated antireflux procedure.

*By Invitation

28. Tracheoplasty with Pericardial Patch for Extensive Tracheal Stenosis in Infants and Children

FAROUK S. IDRISS, SERAFIN Y. DeLEON*,

MICHEL N. ILBAWI*, CAROL GERSON*,

GABRIEL F. TUCKER * and LAUREN HOLINGER*

Chicago, Illinois

Long tracheal stenosis due to complete trachea! rings or other causes presents a difficult problem in management and a serious threat to life in infants and children. Primary resection and anastomosis cannot be accomplished because of the extent of the lesion, which may involve more than two-thirds of the length of the trachea. Few and occasional successes are reported with various surgical techniques. Three patients, ages 4, 7, and 21 months, were operated upon during the past 2 years. A long pericardial patch was used for the tracheoplasty performed through a median sternotomy incision with partial cardiopulmonary bypass. The first patient operated upon was a 7-month old with complete tracheal ring and a right upper lobe tracheal bronchus. His lesion required patching from 1 cm proximal to the larynx down to the carina. A second operation 5 months later was performed to patch 2-3 rings proximal to the carina which were not enlarged during the first surgery. He is asymptomatic one year following surgery. The second child, operated upon at 21 months of age, had agenesis of the left lung. Acute respiratory difficulty may have been precipitated by superimposed infection. She is doing well 9 months postoperatively. The third patient operated upon was a 4-month old who was transferred to our institution in extremis and who could not be bronchoscoped until partial bypass was instituted (1-2 mm tracheal lumen). In this infant, posterior tracheal indentation was caused by a right aortic arch. However, the anterior pericardial patch is fixed and does not collapse. We conclude from this encouraging limited experience that pericardium is a good substitute for extensive tracheal patching, and the median sternotomy incision provides excellent exposure of the entire tracheobronchial tree and permits easy institution of extracorporeal circulation. Bronchoscopic guidance is important during surgery and can be accomplished safely while on bypass. Prolonged tracheal stenting is not required. Early and aggressive management with this technique is recommended for this high-risk group of infants.

5:00 p.m. Executive Session (Members Only) - Grand Ballroom - Third Floor

7:00 p.m. Presidents Reception - Trianon Ballroom, New York Hilton

*By Invitation