Management of asymptomatic mild aortic stenosis during coronary artery operations.

BACKGROUND: Management of asymptomatic mild aortic stenosis at the time of coronary artery bypass grafting (CABG) remains controversial. We have retrospectively analyzed a cohort of patients requiring aortic valve replacement (AVR) subsequent to CABG and compared their operative morbidity and mortality with that of a group receiving CABG and AVR simultaneously at the first operation. METHODS: Analysis is drawn from 28 patients who required AVR 8 +/- 4 years subsequent to CABG (group A) and 175 patients receiving AVR along with CABG at the primary operation (group B). Groups were similar with respect to age, sex, risk factors for cardiac disease, extent of coronary artery disease, left ventricular function, New York Heart Association class, aortic valve area, number of grafts, and size of prosthesis inserted. RESULTS: Patients having AVR subsequent to CABG had a significantly prolonged aortic cross-clamp time and global myocardial ischemic time and incurred a twofold increase in operative mortality. The actuarial survival at 10 years was not significantly different between cohorts. In the 28 patients in group A, the aortic valve area during the period between operations decreased 0.05 mm2/y. CONCLUSIONS: The operative mortality and morbidity of a second operation for AVR is high, but there is no significant difference in survival at 10 years. In at least a portion of patients having mild aortic stenosis at the time of CABG there will be progression of the stenosis necessitating reoperation at a later date.

Relation between pulmonary venous flow and pulmonary wedge pressure: influence of cardiac output.

Multiple factors affect the systolic and diastolic components of pulmonary venous flow. It has been suggested that left ventricular function might influence the effects of filling pressures on indexes of pulmonary venous flow. The present study was designed to evaluate the effect of the pulmonary wedge pressures, left ventricular function, and cardiac output on the pulmonary vein flow pattern. Forty-five patients undergoing cardiac surgery were included in this study. Pulmonary venous flow and mitral flow variables were obtained by transesophageal echocardiography with hemodynamic variables obtained simultaneously. In the total group, there was no consistent relation between the pulmonary venous flow or the mitral flow parameters and the capillary wedge pressures. When patients were grouped according to normal (> 2.2 L/min/m2) or low (< 2.2 L/min/m2) cardiac index, a significant and positive relation was found between the systolic component of the pulmonary venous flow and the pulmonary wedge pressure in patients with normal cardiac index (r = 0.69; p = 0.003). Conversely, in patients with low cardiac index there was also a significant although negative correlation between the systolic velocity integral and the pulmonary wedge pressure (r = -0.58; p < 0.001). In conclusion, the systolic component of the pulmonary venous flow correlates closely and significantly with the capillary wedge pressures. The direction of this relation depends to a large extent on the total cardiac output and to a lesser extent on the left ventricular systolic function as assessed by the ejection fraction.

Reinfusion potassium blood cardioplegia versus cold blood reinfusion alone in elective revascularization.

The purpose of this study was to determine if the addition of potassium to reinfusion cold blood cardioplegia (CBC) offers an advantage over cold blood alone. Forty patients matched for age, left ventricular function, extent of coronary disease and number of vessels bypassed were prospectively randomized. Each patient received an initial dose of CBC (10 cc/kg) with potassium. Group I patients (n = 23) received subsequent infusions of CBC (5 cc/kg) containing potassium while Group II patients (n = 17) received cold blood only. The cross-clamp time, mean infusate volume and temperature were not significantly different in the two groups. Following reperfusion, the cardiac index and the CPK isoenzyme release at 0.5, 1, 8, and 12 h after cross-clamp release were not significantly different between the groups. The postoperative appearance of new Q-waves, inotropic agent requirement, and reversal of the lactate dehydrogenase (LDH) isoenzyme ratio were also not significantly different in the two groups. The study demonstrated that following initial arrest with potassium, cold blood is equally as effective as potassium blood cardioplegia in protecting the ischemic myocardium.

Vascular complications from intraaortic balloons: risk analysis.

PURPOSE: The purpose of this study was to assess the incidence of and predictors for vascular complications in patients who required perioperative intraaortic balloon pump (IABP) support. METHODS: Data from 580 patients collected with a retrospective review were statistically analyzed with 25 perioperative parameters, and significant variables were evaluated with multivariate analysis. These data were also statistically compared with data from a 1983 study from our institution. RESULTS: Vascular complications occurred in 72 patients (12.4%). The three aortic perforations were fatal. Ipsilateral leg ischemia occurred in 69 patients. Of these, ischemia was resolved in 82% of patients by IABP removal (21), thrombectomy (21), vascular repair (13), fasciotomy (2), or without intervention (2). Six patients died with the intraaortic balloon in place. Four patients required amputation for ischemia, but all survived. CONCLUSIONS: Vascular complications were not predictive of operative death (p = 0.26). Risk analyses with 25 perioperative parameters revealed that history of peripheral vascular disease, female sex, history of smoking, and postoperative insertion were independent predictors of vascular complications. However, most risk for vascular complications cannot be explained by these factors because of a low R2 value. Compared with the results of our 1983 study, the incidence of IABP-related complications has not changed, but the severity of complications has decreased significantly, and IABP-induced death has decreased significantly.

Inferior epigastric artery for myocardial revascularization.

From March 1990 through January 1992, 108 patients undergoing myocardial revascularization had one (91) or both (17) inferior epigastric arteries (IEA) used for myocardial revascularization. The internal thoracic artery (ITA) was used bilaterally in 87 patients. Of the 373 distal anastomoses, 210 (56%) were with the ITA, 130 (35%) with the IEA, and 12 (3%) with the gastroepiploic artery. Nineteen patients (18%) received 21 saphenous veins. When compared with the ITA, the IEA demonstrated a longer harvest time (36.5 vs 29.6 min, P < 0.0001), a shorter usable length (11.9 cm vs 16.5 cm, P < 0.001), and similar flow (49.7 cc/min vs 48.7 cc/min, P = NS). The operative mortality was 2.8%. Two deaths resulted from low cardiac output and the one remaining death from complications of a cerebral vascular accident. The most common major complication was respiratory insufficiency, which occurred in 11 patients (12%). There were two sternal infections (2%), and two abdominal wound infections (2%), none of which were fatal. The IEA is an acceptable additional arterial conduit. It can be safely employed with one or both ITAs. Short-term and long-term patency must be established before preferential use of this conduit is advised.

Intraaortic balloon pumping in patients requiring cardiac operations. Risk analysis and long-term follow-up.

The intraaortic balloon pump is usually the first mechanical device inserted for perioperative cardiac failure; however, little current information is available regarding short- and long-term effectiveness. From January 1983 through November 1990, 6856 adult patients underwent cardiac surgical procedures, 580 of whom (8.5%) had an intraaortic balloon inserted preoperatively (107 patients), intraoperatively (419 patients), or postoperatively (54 patients). There were 374 men and 206 women with a mean age of 63.9 years (range 19 to 88). Operations included 376 coronary artery bypass grafts, 100 mitral valve replacements (with or without bypass grafting), 70 aortic valve replacements (with or without bypass grafting), 15 double valve replacements (with or without bypass grafting), and 32 other procedures. There were 72 (12.4%) complications related to the balloon pump, of which 42 necessitated surgical intervention including thrombectomy (21), vascular repair (13), fasciotomy (2), aortic repair (1), and amputation (4). Operative mortality for patients supported by the balloon pump was 44%. Multivariate stepwise analysis of 27 parameters revealed six independent predictors of mortality: preoperative New York Heart Association class, transthoracic intraaortic balloon insertion (both p < 0.0001), preoperative administration of intravenous nitroglycerin, age, female gender, and preoperative balloon insertion (p < 0.001). Balloon-related complications were not predictive of death. Of the 326 hospital survivors, only 34 were lost to follow-up. There were 75 late deaths, the cause of which was cardiac in 41 (55%), noncardiac in 20 (27%), and unknown in 14 (19%). Actuarial survivals at 1, 5, and 9 years are 51%, 42%, and 33%. Of the 217 hospital survivors still alive and contacted, 81% were in class I (114) or II (60). These data demonstrate (1) operative mortality for patients requiring an intraaortic balloon in the perioperative period remains high, (2) perioperative risk factors can be identified, (3) complications related to the balloon pump do not affect survival, (4) operative survivors can achieve prolonged survival with excellent functional results, and (5) consideration for alternative methods of circulatory support is justified.

Aortic valve replacement. Aortic root versus coronary sinus perfusion with blood cardioplegic solution.

The role of retrograde coronary sinus cardioplegia in patients undergoing aortic valve replacement for aortic stenosis alone or in combination with myocardial revascularization has not been fully defined. Sixty-three patients undergoing elective aortic valve replacement received cold potassium blood cardioplegic solution via either the aortic root (36 patients) or the coronary sinus (27 patients). The patients were similar with respect to age, degree of aortic stenosis, ventricular function, severity of coronary artery disease, crossclamp time, completeness of revascularization, and mean volume and temperature of the infusion solution. The mean septal temperature and the release of myocardium-specific isoenzyme in the first 2 hours after crossclamp removal was higher in the retrograde group (p less than 0.008). Right and left ventricular function was preserved equally in the two groups, and volume-loading studies suggested improved diastolic performance in patients having retrograde cardioplegia. There were no differences between the two groups with respect to clinical outcome. We conclude that coronary sinus cardioplegia is as safe as aortic root perfusion for myocardial preservation in patients undergoing elective aortic valve replacement.

Mitral valve replacement: randomized trial of St. Jude and Medtronic-Hall prostheses.

To better define the merits of the bileaflet and tilting-disc valves, we prospectively randomized 102 patients (mean age, 57 years; range, 11 to 85 years) to receive either the St. Jude (n = 55) or the Medtronic-Hall (n = 47) mitral valve prosthesis between September 1986 and May 1991. The two groups were not different with respect to preoperative New York Heart Association class, incidence of mitral stenosis and insufficiency, angina score, extent of coronary artery disease, ventricular function, completeness of revascularization, or cross-clamp or bypass time. The hospital mortality (14.5% versus 10.6%, St. Jude versus Medtronic-Hall) and late mortality (7.3% versus 2.1%) were not significantly different. Follow-up was complete in 84 of 89 hospital survivors (94%) with a mean of 26 months (range, 1 to 60 months). The linearized rates of valve-related events and the 3-year actuarial survival demonstrated no significant differences between both cohorts. Comparison of the clinical outcome and echocardiographic parameters obtained at the time of follow-up demonstrated no significant differences between the two prostheses. These data indicate that the Medtronic-Hall and St. Jude mitral prostheses are similar with respect to their rates of valve-related complications and hemodynamic profiles. This study suggests that there is no difference between the St. Jude and Medtronic-Hall prostheses with regard to early clinical performance or hemodynamic results and therefore does not support the preferential selection of either prosthesis.

Revascularization with bilateral internal thoracic artery grafts in patients with left main coronary stenosis.

Left main occlusive disease (LMD) is a potentially fatal lesion which is optimally treated with surgical revascularization. Although the internal thoracic artery (ITA) is recognized as having superior long term patency, there has been concern regarding possible flow limitation. Because of this concern, there may be reluctance to use only this conduit in patients with LMD in whom high graft flows are desirable. From 1985 to 1990, 45 patients (38 males, 7 females) with LMD ranging in age from 37 to 75 years (mean 55.9 +/- 8.7) underwent revascularization using bilateral ITA grafts placed to the left anterior descending and circumflex arteries. The right ITA was used as a free graft in 19 of 45 (42%) patients and the left ITA was used as a free graft in 3 of 35 (7%). No saphenous vein grafts were placed to the left coronary system in any patient. Over half of these patients (24 patients, 53%) also had occlusive disease in the right coronary artery. A saphenous vein graft was placed to the right coronary artery in 22 of 45 (49%) patients. Ventricular function in this patient subset was good (mean LV score 7.1 +/- 2.1). Intra-operative ITA graft flows were 49.7 +/- 29.1 ml/min for grafts to the left anterior descending and 45.5 +/- 31.7 ml/min for circumflex grafts. There were no perioperative deaths. Morbidity included myocardial infarction, stroke and reoperation for bleeding in 1 patient each (2.2%). Low cardiac output occurred in 2 patients (4.4%). No patient had a mediastinal wound infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Fifteen-year follow-up for double internal thoracic artery grafts.

The internal mammary artery (IMA) is the conduit of choice for myocardial revascularization. From 1972 to 1989, 586 patients received bilateral IMA and supplemental vein grafts. There were 506 men (86%) and 79 women (14%) with a mean age of 55.5 years (range 32-77 years). Unstable angina was present in 138 patients (24%), insulin-requiring diabetes mellitus in 83 (14%) and previous myocardial infarction (MI) in 25 (4%). Preoperative angiography demonstrated triple-vessel disease in 286 patients (49%) and double-vessel disease in the remaining 300 patients (51%). Left main coronary artery disease (stenosis greater than or equal to 50%) was present in 53 (9%). The mean left ventricular score was 7.4 with a range of 5 to 20. The mean number of grafts performed was 3.4 per patient. Hospital mortality was 3.6% (21 patients). Follow-up was done through direct patient contact, via the patient's physician or by telephone contact with the patient themselves or surviving family members. Follow-up was complete in 518 hospital survivors and ranged from 1 month to 17.5 years with a cumulative follow-up of 911 patient years. At 10 and 15 years, respectively, the actuarial freedom from MI was 78% and 72% and freedom from reoperation was 93% and 86%. Actuarial survival at 10 and 15 years was 85% and 70%, respectively. This longitudinal analysis demonstrates that bilateral IMA grafting has a low operative risk. The data suggest that utilization of two IMA grafts yield excellent freedom from recurrent symptoms and provides excellent long-term survival.

Myocardial preservation using lidocaine blood cardioplegia.

Prevention of ventricular fibrillation after aortic unclamping using lidocaine hydrochloride as an additive to cold potassium blood cardioplegia was studied prospectively in 46 patients undergoing elective myocardial revascularization. Patients were similar with respect to age, ventricular function, severity of coronary artery disease, cross-clamp time, completeness of revascularization, frequency of internal thoracic artery grafting, systemic temperature at the time of cross-clamp removal, and mean infusate volume and temperature. Patients receiving lidocaine blood cardioplegia (group 1, 23 patients) had a significant reduction in the incidence of ventricular fibrillation (22% versus 74%; p less than 0.0005) and in the mean number of cardioversion attempts required to defibrillate the heart (0.5 +/- 1.3 versus 1.9 +/- 0.97; p less than 0.0005) after cross-clamp removal compared with controls (group 2, 23 patients). There were no differences between the two groups postoperatively with regard to cardiac enzyme release, hemodynamic measurements, or clinical outcome. Patients receiving lidocaine blood cardioplegia tended to have a lower incidence of new postoperative atrial fibrillation (9% versus 26%). Ventricular function was preserved equally in both groups. We conclude that lidocaine is a safe additive to potassium blood cardioplegia and significantly reduces the incidence of ventricular fibrillation after aortic unclamping.

Acute aortic valvular incompetence following blunt thoracic deceleration injury: case report.

Blunt trauma leading to aortic valvular incompetence is rarely encountered, with 27 cases reported to date. All cusps and commissures are involved to a similar degree. Treatment includes either reattachment of cusps to the annulus (80% recurrence of incompetence) or valvular replacement (no recurrence). Valve replacement is the treatment of choice for these patients.

Aortic valve decalcification.

Ultrasonic decalcification of the aortic valve was performed in 22 elderly patients with critical aortic stenosis (aortic valve areas less than 0.8 cm2) as an alternative to prosthetic valve replacement. All of the patients had symptoms. The mean New York Heart Association class was 3.3 +/- 0.9. Adequate decalcification with restoration of leaflet mobility was achieved in all patients, including seven with bicuspid aortic valves. Leaflet perforation occurred and was successfully repaired in five patients. Ten patients underwent concomitant myocardial revascularization. There were two operative deaths (9%) and three late deaths. Echocardiograms were obtained preoperatively, postoperatively, and at 6 months. The mean aortic valve area increased significantly from 0.72 +/- 0.17 to 1.42 +/- 0.31 cm2 (p less than 0.001) and the peak gradient decreased from 74 +/- 34 to 25 +/- 13 mm Hg (p less than 0.001). At 6 months the aortic valve area (1.29 +/- 0.48 cm2) and peak gradient (31 +/- 12 mm Hg) continued to be significantly better than the preoperative measurements (p less than 0.001), but the 6-month aortic valve area was slightly decreased and the gradient increased when compared with the immediate postoperative values (p less than 0.02). The prevalence of mild to moderate aortic insufficiency increased from 50% of the patients preoperatively to 87% at 6 months (p less than 0.05). Two patients subsequently required aortic valve replacement for restenosis and aortic insufficiency. Ultrasonic decalcification is effective in relieving aortic stenosis, but subsequent restenosis and insufficiency may limit its application.

Reoperation in the intensive care unit.

From July 1, 1984, through June 30, 1989, after 1,259 open heart operations, 110 patients (8.7%) underwent 162 early reoperations either in the intensive care unit (144 procedures) or in the operating room (26 procedures). Reexploration for bleeding (49 procedures) (3.9%) and intraaortic balloon removal (50 procedures) (4.0%) were the two most common procedures. Ninety percent and 96% of these procedures, respectively, were performed in the intensive care unit. Mediastinal infections occurred in 4 (6.1%) of 66 patients undergoing repeat mediastinal operations for all indications. No infection occurred after reexploration for bleeding nor did mediastinal infection occur after reoperation in the intensive care unit. Postoperative death in these 110 patients was not related to reoperation except possibly in the case of 1 patient (0.9%). Average transit time to and from the operating room for patients returned there for reoperation was 89.7 minutes. Charges for procedures performed in the operating room were at least twice as great as for those performed in the intensive care unit. This experience supports expanded use of reoperation in the intensive care unit, as it is safe, effective, economical, and convenient.

Results of internal thoracic artery grafting over 15 years: single versus double grafts.

One hundred consecutive patients who had coronary artery bypass grafting using both internal thoracic arteries (ITAs) and saphenous veins, operated on during a 3-year period between 1972 and 1975, have been compared retrospectively with a series of 100 patients operated on during the same period who had one ITA graft along with saphenous vein grafts. The two groups were similar with respect to age, sex, risk factors for coronary artery disease, angina class, extent of coronary artery disease, left ventricular function, number of coronary bypass grafts performed, and completeness of revascularization. Single ITA operative mortality was 2% and double ITA, 9% (p = NS). The mean follow-up of hospital survivors was 14.4 +/- 2.7 years; all but 7 patients had follow-up for at least 10 years. At 13 years, the actuarial patency of the right ITA was 85% and the left ITA, 82%. These data strongly suggest a survival benefit for patients with double ITA grafts among hospital survivors (74% versus 59%; p = 0.05). Patients receiving two ITA grafts had a significant freedom from subsequent myocardial infarction (75% versus 59%, p less than 0.025), recurrent angina pectoris (36% versus 27%, p less than 0.025), and subsequent total ischemic events (32% versus 18%, p less than 0.01). These data also suggest improved freedom from coronary artery interventional therapy (percutaneous transluminal coronary angioplasty and reoperation) when two ITA grafts were used. These results support the use of bilateral internal thoracic artery grafting in selected patients.

Relation of silent myocardial ischemia after coronary artery bypass grafting to angiographic completeness of revascularization and long-term prognosis.

The prevalence and characteristics of silent myocardial ischemia as detected by 24-hour ambulatory electrocardiography ST-segment depression were prospectively assessed in 94 patients examined early (1 to 3 months) and 184 patients examined late (12 months) after coronary artery bypass grafting (CABG), and followed for a mean of 48 +/- 11 (range 4 to 62) months. The relation of ambulatory electrocardiographic silent ischemia to evidence of completeness of revascularization as defined by cardiac angiography performed 1 and 12 months after CABG, and to prognosis by follow-up of adverse clinical events was analyzed. Silent ischemia was detected early in 20% (19 of 94) and late in 27% (50 of 184) of patients, and showed a mean frequency of episodes ranging from 6 to 10 episodes/24 hours with a mean duration ranging from 15 to 23 minutes. The circadian distribution of episodes disclosed a significant peak of ischemic activity during the period of 6 A.M. to noon and a secondary peak between 6 P.M. and midnight (p less than 0.01 and p less than 0.001, respectively). Silent ischemia was not found by univariate analysis to be associated with graft or anastomotic site occlusions, low graft flow rates, grafted arteries with significant distal residual stenoses or ungrafted stenotic native coronary arteries. Kaplan-Meier analysis of time to cardiac event showed that silent ischemia was not predictive of an adverse clinical event in the early years after CABG. Cox regression analysis of 30 covariates only disclosed age (relative risk 1.06 [95% confidence interval, 1.01 to 2.94]) as having an effect on time to adverse clinical event.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac surgery in the octogenarian.

The increasing safety of cardiac surgery has led to the frequent referral of octogenarians for operation. Between 1980 and 1989, we reviewed our experience with 103 octogenarians (59 male, 44 female; mean age 82 years) to determine the surgical risk factors and outcome in the elderly population. There were 71 coronary bypasses (CABG), 11 aortic valve replacements (AVR), 11 AVR-CABG, 4 mitral valve replacements (MVR), 3 MVR-CABG and 3 AVR-MVR-CABG. Seventeen patients died during hospitalization (16.5%) including 9 CABG (13%); 1 AVR (9%), 2 AVR-CABG (18%), 2 MVR (50%), 1 MVR-CABG (33%) and 2 AVR-MVR-CABG (67%). Statistical analysis of 22 perioperative variables suggested that a preoperative intraaortic balloon, a history of congestive heart failure, mitral valve replacement, urgent operation, need for preoperative inotropic support and the number of anastomoses performed were significant or marginally significant (P less than 0.15) univariate predictors of operative mortality. Multivariate analysis revealed that the need for a preoperative intraaortic balloon (F = 13.1), history of congestive heart failure (F = 6.8), and MVR (F = 6.7) were significant (P less than 0.001) independent predictors of mortality. Postoperative complications included arrhythmias in 36 patients (35%), respiratory insufficiency in 11 (11%), reversible neurological deficit in 15 (14%), and a permanent neurological deficit in 6 patients (6%). Actuarial survival was 90% and 82% at 1 and 2 years, respectively. Seven of 86 (8%) long term survivors sustained a stroke in the follow-up interval. The mean follow-up of survivors was 23 +/- 19 months with a mean improvement in NYHA class of 1.4 (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)