Preoperative Intra-aortic Balloon Pump Research Articles

Gastrointestinal complications following cardiac surgery

This study sought to determine which factors influence the mortality rate in patients developing gastrointestinal complications following cardiac surgery. Between July 1988 and January 1992, 2054 patients underwent cardiac surgical procedures at the Boston University Medical Center. Of these, 29 (1.4%) developed postoperative gastrointestinal complications. The overall mortality rate among these patients was 27% ( 8 29 ). Those who died following such complications had a higher incidence of New York Heart Association (NYHA) class IV and unstable symptoms ( 8 8 , 100% versus 3 21 , 14%; P < 0.0001), and an increased need for preoperative intra-aortic balloon pump support ( 4 8 . 50% versus 1 21 , 5%; P < 0.004). The need for gastrointestinal surgical intervention increased the mortality rate significantly compared with patients managed medically ( 8 18 , 44% versus 0/11, 0%; P < 0.01). Patients with ischemic bowel also had a significantly higher mortality ( 5 5 , 100% versus 3 24 , 12%; P < 0.001). It is concluded that most patients with gastrointestinal complications following cardiac surgery can be treated, and with acceptable mortality rates. The presence of unstable symptoms, preoperative intra-aortic balloon pump support, ischemic bowel and the need for gastrointestinal surgical intervention adversely affect mortality.

Evaluation of leukocyte-depleted terminal blood cardioplegic solution in patients undergoing elective and emergency coronary artery bypass grafting

Leukocyte depletion at reperfusion may have a role in myocardial protection when combined with terminal cardioplegia. We applied this method in a selected group of 68 patients with coronary artery bypass grafting either for elective surgical procedures (n = 38) or emergency surgical procedures with the use of a preoperative intraaortic balloon pump (n = 30) because of developing acute myocardial infarction. Basic cold potassium crystalloid cardioplegic solution was used. During delivery of leukocyte-depleted terminal cardioplegic solution, warm arterial blood delivered from cardiopulmonary bypass was passed through a leukocyte removal filter, mixed with potassium crystalloid cardioplegic solution, and administered to the aortic root for the first 10 minutes of reperfusion. Patients were randomized into three groups for reperfusion: whole blood, terminal cardioplegic solution, and leukocyte-depleted terminal cardioplegic solution reperfusion groups. In elective coronary artery bypass grafting, no significant difference was found in the clinical data. However, in emergency coronary artery bypass grafting, the leukocyte-depleted terminal cardioplegic solution group (n = 10) showed significantly lower peak creatine kinase MB levels (leukocyte-depleted terminal cardioplegic solution versus terminal cardioplegic solution versus whole blood: 27 +/- 11, 56 +/- 13, 74 +/- 18, respectively; p < 0.05) and maximum dopamine doses required at the weaning of cardiopulmonary bypass (6.3 +/- 1.1 versus 11.2 +/- 3.3 versus 9.2 +/- 2.2; p < 0.05) than did the terminal cardioplegic solution (n = 10) and whole blood groups (n = 10). Moreover, the leukocyte-depleted terminal cardioplegic solution group showed significantly lower difference of malondialdehyde between arterial and coronary sinus blood (0.15 +/- 0.09 versus 0.36 +/- 0.06 versus 0.06 +/- 0.12 nmol/ml, p < 0.05) than did the terminal cardioplegic solution or whole blood groups. These results showed that leukocyte-depleted terminal blood cardioplegic solution may have a role in attenuating reperfusion injury in patients with critical conditions such as preoperative myocardial ischemic injury.

Reoperative coronary grafting: Changing patient profiles, operative indications, techniques, and results

To assess the changing trends in patient profiles, operative indications and techniques, and their impact on the results of reoperative myocardial revascularization, we reviewed the records of 750 consecutive patients who had an isolated first reoperation for coronary artery disease at the Massachusetts General Hospital from 1977 to 1992. The patients were chronologically grouped into three equal cohorts of 250 patients. Our assessment over time revealed a significantly ( p < 0.03) increased incidence of the following: older age, peripheral vascular disease, grafts at the first revascularization, longer operative interval, interval infarctions and angioplasties, and congestive heart failure and unstable angina requiring greater use of preoperative intraaortic balloon pumping. At catheterization significantly more left main coronary disease, lower ejection fractions, and more patent but diseased grafts were found. The reoperations were significantly done more urgently, with more grafts placed and a greater use of mammary artery grafting. Despite these increased risks over time, median postoperative hospital stay was significantly shortened ( p < 0.001), though hospital mortality (5.3%) and perioperative myocardial infarction (63%) did not change significantly. Significant multivariate predictors of hospital death were nonelective operation, perioperative myocardial infarction, prior myocardial infarction, and mammary artery grafting at the initial operation.

Changing patterns of patients undergoing emergency surgical revascularization for acute coronary occlusion: Importance of myocardial protection techniques

Between 1977 and 1992 a total of 163 consecutive patients underwent emergency coronary artery bypass grafting after acute coronary occlusion (94% after failed angioplasty). Patients were divided into four groups according to the method used for myocardial protection. The crystalloid cardioplegia group included 30 patients operated on from 1977 to 1980; the hypothermic fibrillation group included 60 patients (1980 to 1986); the blood cardioplegia group included 36 patients (1986 to 1989); and the blood cardioplegia with controlled reperfusion group included 37 patients (1989 to 1992). Preoperative data, ischemic time interval, collateral blood flow, intraoperative data, regional wall motion, global ejection fraction, myocardial infarct-specific electrocardiographic changes, enzyme release, rhythm disturbances, mortality, prevalence of intraaortic balloon pumping, and inotropic support were assessed in this retrospective study. Our data indicate that the current spectrum of patients undergoing emergency coronary artery bypass grafting after acute coronary occlusion are at a significantly higher risk compared with those 15 years ago, that is, increase in age (53 +/- 1 versus 59 +/- 2 years; p < 0.05), three-vessel disease (38% versus 3%; p = 0.004), acute occlusion of the left main coronary artery (11% versus 0%; p = 0.02), preoperative cardiogenic shock (35% versus 3%; p = 0.007), prevalence of acute two-vessel occlusion (22% versus 3%; p = 0.05), prevalence of previous infarction (59% versus 23%; p = 0.04), and duration of ischemia (3.0 +/- 0.2 versus 4.1 +/- 0.3 hours; p < 0.05). Despite the increase in patients with severely compromised ventricular function during recent years, the overall hospital mortality decreased to 5% (2/37) when maximal protection of the ischemic and remote myocardium was performed (preoperative intraaortic balloon pump, combined antegrade/retrograde substrate-enriched blood cardioplegia, warm induction, controlled reperfusion, prolonged vented bypass). Single-vessel disease was always associated with a low mortality, whereas mortality could be reduced with controlled blood cardioplegia in patients with multivessel disease (6%) and cardiogenic shock (15%). The immediate return of regional contractility in the previously ischemic area after controlled reperfusion might serve as an explanation for these favorable results. After unmodified blood reperfusion, normokinesis or slight hypokinesis occurs in only 34% to 46% in the early postoperative period (1 to 4 weeks) in comparison with 86% after controlled blood cardioplegia reperfusion (p < 0.05). We conclude that there is a significant increase in risk factors in patients undergoing emergency coronary artery bypass grafting and that improved methods of intraoperative myocardial protection are needed for these compromised patients.

Results of early repair of ventricular septal defect after an acute myocardial infarction

A 10-year experience with early operation for postinfarction ventricular septal defect is reviewed. Twenty-two patients underwent surgical repair; operative mortality was 36% (< 30 days). The actuarial survival was 64% at 1 month, 59% at 1 year, and 47% at 5 years. Risk factors predictive of operative mortality were diabetes (p = 0.001), elevated preoperative right atrial pressure (p = 0.02), the absence of a preoperative intraaortic balloon pump (p = 0.006), and a short time interval between infarct and operation (p = 0.018). Long-term survival was adversely related to diabetes (p = 0.030), elevated preoperative right atrial pressure (p = 0.005), and, surprisingly, survival was better in patients with a greater extent of coronary artery disease (p = 0.023). There were 14 operative survivors (64%) and 11 long-term survivors (3 months to 10 years, mean 6.0 +/- 3.5 years). Six of eleven survivors were in functional New York Heart Association class I, one was in class II, and four were in class III.

Applicability of noncardioplegic coronary bypass to high-risk patients

Although some surgeons still prefer noncardioplegic coronary bypass, most surgeons are skeptical of its suitability for high-risk patients. We analyzed the first 3000 patients who had primary coronary bypass without cardioplegia since our program's inception. Patients with reoperations, valve operations, or carotid endarterectomies were excluded. Multivariate predictors of operative death included age, sex, left ventricular dysfunction, preoperative intraaortic balloon pumping, and urgency of operation. Eight hundred seventy-nine patients (29%) were more than 70 years of age; 795 (27%) were female; 290 (9.7%) had an ejection fraction less than 0.30, and another 77 (2.6%) had left ventricular aneurysms; 196 (6.5%) had an acute myocardial infarction, and another 397 (13%) had a myocardial infarction less than 1 week preoperatively; 917 (31%) had rest pain in the hospital (preinfarction angina). Only 790 (26%) had elective operations. The overall operative mortality rate was 1.47% (44/3000): The mortality rate for elective operations was 0.5% (4/790); urgent 1.7% (28/1687); emergency 2.3% (12/523). In patients with an ejection fraction less than 0.30 the mortality rate was 6.2% (18/290); with age more than 70 years, it was 3.9% (34 of 879); with acute myocardial infarction it was 3.1% (6/196); and with left ventricular aneurysmectomy it was 1.3% (1/77). Inotropic support after leaving the operating room was needed in 6.6% (199 patients), and 1% (30 patients) required new intraaortic balloon pumping postoperatively (two of these 30 patients died). These results provide reassurance that noncardioplegic coronary artery bypass grafting provides excellent myocardial protection and operating conditions for primary coronary bypass and is particularly suitable for high-risk patients.

Acute postinfarction septal rupture: Long-term results

From 1973 to 1989, 66 patients received early surgical repair for acute postinfarction ventricular septal rupture. Mean age was 64 ± 7 years (range, 45 to 80 years). Ventricular septal rupture occurred soon after acute myocardial infarction (3.4 ± 4 days), and the first medical treatment occurred 6.7 ± 7 days after onset of acute myocardial infarction. Three patients had a previous myocardial infarction. The site of the rupture was anterior in 38 patients (57%) and posterior in 28 (43%). Forty-four patients (67%) were in shock at the time of admission. Intraaortic balloon pumping was used pre-operatively in 28. Operation was performed at the time of maximal efficacy of medical treatment. The same technique was used in all cases. Associated procedures included coronary bypass grafting in 5 patients and valvar operation in 5. The patients have been carefully followed up for up to 16 years. Hospital mortality was 45% (30 patients) and was cardiac related or due to acute renal failure in 25 patients (83%). No correlation could be revealed between early death and age, sex, preoperative intraaortic balloon pumping, or year of operation. Location of the ventricular septal rupture (early mortality of 57% for posterior versus 37% for anterior ventricular septal rupture) and shock at the time of admission (52% versus 32%) showed a trend toward significance (0.08 ≤ p < 0.10). Response to initial active therapy has a strong predictive value (mortality of 70% in unresponsive patients versus 14% in responders; p < 0.001). The actuarial survival rate was 56% ± 6% at 1 year, 44% ± 6% at 5 years (n = 23), and 26% ± 10% at 10 years (n = 10). The cause of late death was cardiac related in 38% of patients. Early surgical repair of early septal rupture after acute myocardial infarction has a high perioperative mortality rate but provides a good quality of life and long-term survival. Improvement should be possible by optimized techniques of myocardial reperfusion and transplantation. The age of the patients and the presence of initial cardiogenic shock make transplantation an infrequent option.

Surgery of post-infarction ventricular septal defect: risk factors for hospital death and long-term results

From December 1971 to December 1989, 62 patients (pts) 42 males, 20 females, mean age 66 years (yr) 6 months (mth) (range 52-80) were operated upon for post-infarction ventricular septal defect (VSD), (anterior 34, inferior 28). Eight pts (13%), group (G) 1 presented with cardiogenic shock, 19 pts (30.5%), G2 with severe congestive heart failure (CHF); 31 pts (50%), G3 were stable with mild CHF and 4 pts (6.5%), G4 without CHF. Preoperative intra-aortic balloon pumping (IABP) was used in 49 pts (79%). One transplanted pt was excluded from this study. The VSD was closed from 1 day (d) to 5 mth (mean 13 d) after its occurrence. Hospital death (HD) occurred in 23 pts (37.7% +/- 6%). Of 44 incremental risk factors (RF) for HD studied, the preoperative status (PS) was the most significant (P less than 0.01). G1: 87% +/- 12%, G2: 42% +/- 12%, G3: 25.8% +/- 8%, G4: 0%. [table: see text] Non-survivors had a shorter mean delay between VSD occurrence and surgery than survivors: 5.6 +/- 3.7 d vs 18.2 +/- 30 d (P less than 0.05), but this delay was correlated to PS. The follow-up of the 38 early survivors ranges from 2 mth to 14 yr (mean 3 yr, 11 mth); 11 pts died between 45 d and 14 yr. No RF was identified for premature late death. HD included, the actuarial survival rate at 1, 5, 10 yr is: 57% (+/- 7%), 44% (+/- 8%), 30% (+/- 10%), respectively.

Timing of coronary revascularization after acute myocardial infarction: Early and late results in patients revascularized within seven weeks

Evidence of ischemia after acute myocardial infarction is a serious complication. If angiography reveals significant coronary artery disease, the precise timing of myocardial revascularization may be of critical importance. From 1978 through 1982, 174 patients underwent myocardial revascularization within 7 weeks of a documented myocardial infarction. The male:female ratio was 138:36, the average age was 58 +/- 1 (SEM) years; and the ejection fractions averaged 41% +/- 1%. Forty-four (25%) patients required preoperative intra-aortic balloon pump support, and an additional 18 (10%) required intra-aortic balloon pumping to be separated from cardiopulmonary bypass. An average of 2.9 +/- 0.1 vessels per patient were bypassed. The hospital mortality for these 174 patients was 16%. When mortalities were categorized according to the postinfarction week in which operation was performed, hospital mortality fell from 46% for those patients operated upon within 1 week of infarction to 6% for those patients operated upon 7 weeks after infarction. Of those patients operated upon within the first week after infarction, 23% were in cardiogenic shock and 62% required preoperative balloon pumping. Clearly the most critically ill patients were operated upon during the early postinfarction period. However, there was a marked difference in survival when patients in each of the seven weekly groups were classified according to ejection fraction. All patients with an ejection fraction greater than or equal to 50% (50 patients) operated upon at any time after infarction survived their hospital course, with only one late death. Conversely, among the 124 patients with an ejection fraction less than 50% operated upon during this 7 week interval, there were 27 (22%) hospital deaths. In this latter group, survival rates steadily improved if revascularization was performed at a time more remote from the infarction. The difference in early and late survival rates of patients operated upon with an ejection fraction greater than or equal to 50% compared to patients with an ejection fraction less than 50% is highly significant (p less than 0.001). We conclude that myocardial revascularization is safe at any time after myocardial infarction for those individuals with an ejection fraction greater than or equal to 50%. However, if the ejection fraction is less than 50%, then operation after myocardial infarction should be delayed at least 4 weeks.

Surgical management of acute myocardial ischemia following percutaneous transluminal coronary angioplasty: Role of the intra-aortic balloon pump

Acute myocardial ischemia is a serious complication of percutaneous transluminal coronary angioplasty, often requiring emergency myocardial revascularization. Since our initial report of 17 such patients, we have encountered an additional 32 patients requiring emergency myocardial revascularization since September, 1981. The indication for emergency myocardial revascularization was ischemic chest pain in all 32 patients. Percutaneous transluminal coronary angioplasty resulted in injury to the right coronary artery in 11 patients, the left anterior descending artery in 19 patients, and the left main artery in two patients. The onset of ischemia was immediate in 26 patients but delayed up to 22 hours in six patients. Chest pain was associated with ST-segment elevation in 21 patients, hypotension in 7 patients, and cardiac arrest in 6 patients. Immediate intra-aortic balloon pumping was instituted in the angioplasty suite in 16 patients. The mean time from onset of ischemia to completed revascularization was 156 minutes with a mean of 1.6 grafts performed per patient. Seventeen patients (53%) had enzyme evidence of myocardial infarction postoperatively, with a significantly higher (p less than 0.01) incidence of myocardial infarction in those patients with preoperative ST elevation (76% versus 9%). In the 21 patients with ST-segment elevation, the incidence of Q wave infarction was 20% (3/15) with balloon pumping and 50% (3/6) without balloon pumping. Complications associated with intra-aortic balloon pumping occurred in one patient (6%). There were no hospital or late deaths with follow-up extending 16 months. The spectrum of injury resulting from percutaneous transluminal coronary angioplasty extends from chest pain alone to severe transmural ischemia with hypotension or cardiac arrest. Presentation may be immediate or delayed. Urgent emergency myocardial revascularization remains the accepted therapy for this complication. Immediate preoperative intra-aortic balloon pumping is a useful adjunct to emergency myocardial revascularization in the group of patients with acute ischemia and ST-segment elevation.

Isolated coronary artery bypass grafting in patients seventy years of age and older: Early and late results

Increasing longevity makes the consideration of coronary bypass common in elderly patients. Seventy-five patients 70 years of age or older undergoing coronary artery bypass grafting (CABG) for angina pectoris were compared to a control group of 75 patients under 70 years of age. The groups were matched for male:female ratio (46:29), previous infarction (28/75), unstable angina (27/75), and the requirement for preoperative intra-aortic balloon pumping (7/75). Patients under 70 years of age had an average preoperative New York Heart Association (NYHA) class of 3.0 +/- 0.6 (SEM) and an average left ventricular end-diastolic pressure of 15.5 +/- 0.8 mm Hg, compared to 3.3 +/- 0.6 and 12.9 +/- 1.1 mm Hg, respectively, for the older group. Average grafts per patient were 2.7 +/- 0.8 in the younger group and 2.8 +/- 0.1 in the older group. Overall operative mortality for patients under 70 was 4% (3/75) versus 12% (9/75) (p = 0.06) for patients 70 and older. The incidence of chronic stable angina was 2% (1/48) versus 6% (3/48) (p = 0.30). Perioperative infarctions occurred in 7% of those under 70 and 5% of those 70 or older (p = 0.54). Those under 70 averaged 13.8 +/- 0.6 postoperative hospital days versus 18.4 +/- 1.2 hospital days for the older group (p less than 0.05). Follow-up ranged from 2 to 94 months, averaging 22 months for patients under 70 and 24 months for those 70 or older. Late cardiac mortality rates were 4% (3/70) in the younger patients and 3% (2/66) in the older patients (p = 0.53). Current NYHA class was 1.3 +/- 0.7 for those under 70, with 9% reporting angina, and 1.4 +/- 0.7 for those who were 70 or older, with 6% reporting angina. CABG can be performed with acceptable risk in older patients and leads to encouraging symptomatic improvement and late survival.

Surgical Therapy for Prinzmetal's Variant Angina

Fifty-two patients underwent coronary artery bypass grafting between 1973 and 1979 for variant angina, defined as pain, usually at rest, associated with S-T segment elevation. Only patients with fixed occlusive coronary artery disease, defined as greater than 70% narrowing in diameter, were included. When fixed coronary artery stenosis is present, variant angina—whether presenting as stable, unstable, or postinfarction angina, and regardless of the number of vessels diseased—is effectively treated by myocardial revascularization. Preoperative intraaortic balloon pumping is a useful therapeutic adjunct in the unstable subset refractory to medical therapy. The results of revascularization in patients with Prinzmetal's variant angina and fixed coronary disease were no different from those in patients with classic angina pectoris of comparable clinical categories.

What Role Should the Intra-aortic Balloon Have in Cardiac Surgery

Intra-aortic balloon pumping (IABP) to assist the failing circulation has become widely applied and accepted since its introduction in 1968. The elective, preoperative use of IABP for patients undergoing cardiac surgery has now become the controversy. The purposes of this report are to examine our experience with IABP and to determine its appropriate role in high-risk patients. IABP was utilized in 75 of 2333 (3.2%) adult cardiac surgical patients at Emory University Hospital from January 1976 through June 1978. IABP was required for refractory shock following cardiopulmonary bypass (CB) in 53 patients, for preoperative cardiogenic shock after acute myocardial infarction (CSMI) in nine and was electively placed prior to CB in 13. Sixty-two patients (81%) were able to separate from CB with IABP and pharmacologic support and were assisted 24-432 hours (median 64 hours). Fifty-five (73%) were weaned from IABP. Fifty (67%) are hospital survivors; late deaths have occurred in six patients (8%). Hemodynamic effect of IABP was demonstrated by comparison of pumping 1:1 to 1:8 mode in five balloon-dependent patients after CB. IABP was found to decrease systolic blood pressure, left ventricular filling pressure and peripheral resistance (p < .05). It increased diastolic and mean blood pressure, cardiac index and the endocardial viability ratio (p < .05). The post-CB use of IABP resulted in highest salvage when utilized to support failing hearts that required surgery despite recent preoperative infarction or when intraoperative ischemic injury had occurred. Poorest results were in patients with extensive chronic myocardial damage. Except in the case of preoperative cardiogenic shock, it was impossible to establish statistically reliable criteria for patients in whom elective preoperative insertion was found to be necessary. Careful surgical and anesthesia management with good monitoring can be used instead of preoperative IABP in the majority of (if not all) hemodynamically stable patients regardless of risk classification.

Preoperative intra-aortic balloon support in surgery for left main coronary stenosis.

Twenty-six patients with left main coronary (LMC) stenosis were operated upon with preoperative intra aortic balloon pump (IABP) support. There was no mortality, and no morbidity attributable to the balloon catheter. The most delicate facet of revascularization surgery in this entity is the pre-cardiopulmonary bypass phase including anesthesia induction during which blood pressure fluctuation may further diminish severely compromised coronary flow. Although systolic pressure dropped to below 100 mm Hg in 50% of patients during induction, there were only two patients with electrocardiographic evidence of perioperative myocardial infarction, and only one who needed rantic institution of cardiopulmonary bypass just after induction. Perioperative logistics were quite trouble free in all 26 patients, in marked contrast to 5 LMC patients operated upon prior to our preoperative IABP concent; 3 of these deteriorated upon induction, with two deaths resulting. Preoperative IABP is a reasonable supportive adjunct in surgery for LMC stenosis.