Intraoperative versus routine hemodialysis in end-stage renal disease patients undergoing open-heart surgery.

Of 13 chronic hemodialysis end-stage renal disease (ESRD) patients undergoing open-heart surgery, 7 received intraoperative hemodialysis (IHD) during cardiopulmonary bypass and 6 received hemodialysis on a routine basis (RHD). Within the groups, IHD patients had significantly lower post-operative mean serum potassium and mean plasma creatinine concentrations compared to mean preoperative values. Postoperative mean BUN tended to decrease and mean serum bicarbonate concentration was unchanged as compared to mean preoperative values. In the RHD group, however, post-operative mean serum potassium concentration tended to increase, mean serum bicarbonate concentration significantly declined and mean BUN was unchanged as compared to mean preoperative values. An average of 2.1 +/- 0.5 liters of fluid was removed from the IHD patients during cardiopulmonary bypass. Post-operatively, 0 of 7 IHD patients versus 4 of 6 RHD patients required parenteral sodium bicarbonate therapy (chi 2, p less than 0.01). On average, RHD patients required hemodialysis 1 day after surgery, whereas IHD patients were hemodialyzed 2 days after surgery (p = 0.009). We conclude that IHD lessened postoperative hyperkalemia and metabolic acidosis and delayed postoperative hemodialysis by an additional day. IHD should be considered as an adjunct to RHD therapy in the management of ESRD patients undergoing open-heart surgery.

The conduction system of the swine heart.

Although the pig has been used as an experimental model for ischemic heart disease and sudden death, relatively little is known about the anatomy of the conduction system (CS) of this animal. We attempted to correlate electrophysiologic and anatomic differences between the pig and human CS. Invasive electrophysiologic studies were performed in five healthy anesthetized pigs. In contrast to the adult human, the pig has sinus tachycardia, shortened PR and H-V intervals, and a relatively short sinoatrial conduction time. Compared with the human CS, serial sections of the CS of pig hearts showed the following differences: (1) the atrioventricular node is located more to the right of the summit of the ventricular septum; (2) the penetrating bundle is very short, and the bifurcation of the bundle into bundle branches occurs more proximally; (3) there is more connective tissue and less elastic tissue; and (4) there is a copious amount of nerve fibers (about 50 percent throughout the CS). The presence of the abundant neural tissue implies that there is an important neurogenic component to conduction in the pig. Because of the above differences from the human, the pig should be used with caution as an experimental model in ischemic heart disease and sudden death where arrhythmias are studied.

Coronary artery bypass surgery prior to resection of abdominal aortic aneurysm in patients with unstable coronary artery disease.

Coronary artery disease (CAD) is associated with abdominal aortic aneurysm in greater than 60% of cases. CAD continues to affect postoperative complication rates. Half of the deaths that follow resection of abdominal aortic aneurysms are due to perioperative myocardial infarctions. On evaluation for surgical resection of an abdominal aortic aneurysm, six patients were found to have significant CAD. Each underwent coronary artery bypass surgery prior to elective resection of the aneurysm. No deaths or myocardial infarctions occurred following any of the procedures. We restrict our indications for coronary angiography to the evaluation of patients with unstable angina (pain at rest or after minimal exertion) in whom noninvasive studies reveal evidence of CAD, and for patients who are unresponsive to medical management.

Surgical revascularization of left main coronary artery stenosis: determinants of perioperative and long-term outcome in the 1980s.

The postoperative courses of 176 patients who underwent coronary artery bypass surgery for significant left main coronary artery stenosis were analyzed to determine which preoperative clinical and angiographic factors correlated best with outcome. Clinical variables included age, sex, New York Heart Association (NYHA) anginal class, presence of unstable angina, and surgical class. The angiographic variables included percentage of left main stenosis, presence of right coronary artery stenosis, coronary dominance, number of vessels diseased, myocardial jeopardy score, and ejection fraction. The overall perioperative mortality rate was 9.1%. There was a significant increase in perioperative mortality among female patients (p less than 0.05) and patients undergoing emergency surgery (p less than 0.05). Patients with left main stenosis of 80% or more or with balanced or left dominant circulation showed trends toward increased perioperative mortality. Life-table analysis showed that emergency surgery and left main stenosis of 80% or more correlated with increased long-term mortality (p less than 0.05). No other variable tested showed a significant correlation with either perioperative or long-term mortality. A comparison of these results with studies performed in the 1970s shows that there has been considerable change in those factors which place a patient at increased risk for mortality during surgical treatment of left main coronary artery stenosis.

Improved survival with coronary bypass surgery in patients with three-vessel coronary disease and abnormal left ventricular function. Matched case-control study in patients with potentially operable disease.

Recent studies have suggested that patients with three-vessel coronary disease and abnormal left ventricular function have better survival rates with bypass surgery than with medical therapy alone. Case-control studies may give accurate survival estimates, but to be valid, selection biases must be taken into account. A matched case-control method was used to compare survival patterns in patients treated medically or surgically during the 1980s. Fifty medical patients with potentially operable coronary disease and 46 surgical patients were matched for significant three-vessel disease and abnormal ventricular function. These two groups had no significant differences with regard to 24 variables, including age (64 +/- 8 versus 63 +/- 10 years), chest pain class, congestive heart failure signs, ejection fraction (36 +/- 8 versus 37 +/- 9 percent), segmental wall score, or a coronary score evaluating lesion site and severity. There were slight differences between the two groups with regard to congestive heart failure symptoms (p = 0.04). Patients undergoing bypass surgery had improved four-year survival rates compared with the medical group (89 versus 55 percent; p = 0.01). Thus, this study used an effective case-control method to suggest that, in the 1980s, coronary surgery improves prognosis substantially in surgically approachable patients with severe coronary disease and ventricular dysfunction.

Medical and surgical survival in coronary artery disease in the 1980s.

The survival of 1,657 patients with angiographically proved coronary artery disease (CAD) was studied for 4 years (mean 2.0 +/- 1.2) during the 1980s to examine the prognostic importance of multiple clinical variables. One hundred of the 1,049 medically treated patients (9.5%) and 31 of the 608 surgically treated patients (5.1%) died. Multivariate analyses revealed that the strongest prognostic variables for survival in the medical group were indexes of left ventricular function (p less than 0.0001), severity of coronary stenoses (p less than 0.0001) and age (p = 0.005). However, only age (p less than 0.0001) was a significant prognostic variable in the surgically treated group. This study emphasizes the lack of prognostic significance of left ventricular function indexes and severity of coronary stenoses in surgically treated patients with CAD. These results continue the trend toward improved surgical survival shown in recent years.

Traumatic coronary artery fistula.

Coronary artery fistulas can occur in patients who survive cardiac trauma. We report one such case with development of a right coronary artery-right atrial fistula 2 years after injury. The literature shows that surgical correction should be performed before the development of incapacitating symptoms (angina, pulmonary hypertension, congestive heart failure). Proximal and distal ligation of the affected coronary artery with distal bypass grafting is the recommended surgical procedure. Other procedures have led to recurrence of the fistula.

General anaesthesia for Nd:YAG laser resection of obstructing endobronchial tumours using the rigid bronchoscope.

Provision of general anaesthesia for patients undergoing Nd:YAG laser resection of obstructing endobronchial tumours using the rigid bronchoscope presents unique problems for the anaesthesiologist. We studied 15 patients who underwent 20 of these procedures under general anaesthesia. Patients were anaesthetized and ventilated with either potent inhalation agents via the side arm of the ventilating bronchoscope (Group I: N = 8), or with intravenous agents and the Sanders jet injector attached to the rigid bronchoscope (Group II: N = 12). Patients were paralyzed and ventilation was controlled. The inspired gas mixture was nitrogen and oxygen, and the FIO2 was decreased to 0.3-0.4 during periods of resection. Group I patients had significantly higher peak pCO2's than Group II (8.3 kPa (62 mmHg) vs. 5.6 kPa (44 mmHg); lowest recorded pO2's were comparable and similar to pre-induction values. Both groups exhibited wide blood pressure fluctuations. Heart rates remained within 15 per cent of pre-induction levels. There were no intraoperative deaths, and no airway fires, massive haemorrhages or pneumothoraces. We conclude that these procedures can be undertaken with the use of general anaesthesia and the rigid bronchoscope, but that patients may encounter potentially serious respiratory or haemodynamic instability during the procedure.

One hundred neodymium-YAG laser ablations of obstructing tracheal neoplasms.

Forty patients with obstructing, nonresectable tracheal neoplasms underwent 100 ablations with the neodymium-yttrium-aluminum garnet (YAG) laser. The laser allows bloodless resection and vaporization of tumors. Unlike the carbon dioxide laser, the neodymium-YAG laser can be used with the flexible bronchoscope and has an excellent effect on coagulation. Thirty-four patients had primary lung malignancies (epidermoid in 24); 4 had metastatic malignancies; and 2 had benign lesions. Results have been excellent in 22, fair in 10, and poor in 8. No patient has died or had a deleterious result. Complications have occurred in only 1 of 89 ablations done with the flexible bronchoscope. We believe that the neodymium-YAG laser is effective in opening major tracheal or bronchial obstructions and offers substantial symptomatic improvement in patients who are short of breath. Although this treatment is only palliative, the results have been excellent in more than half of the patients.

Successful management of right ventricular failure with the ventricular assist pump following aortic valve replacement and coronary bypass grafting.

Right ventricular failure is an infrequent but potentially lethal complication of cardiac surgical procedures. We have successfully treated a patient with right ventricular failure with the use of a right ventricular assist pump (RVAP). This patient had aortic stenosis and coronary artery disease involving the circumflex and right coronary arteries. He also had chronic obstructive pulmonary disease with mild pulmonary hypertension (mean pulmonary artery pressure of 26 mm Hg) and evidence of mild right ventricular failure (right ventricular pressure of 40/14 mm Hg). Gated radionuclide angiography, performed preoperatively, showed that the right ventricle had normal wall motion. Right ventricular failure prevented discontinuation of cardiopulmonary bypass despite use of an intra-aortic balloon pump. The right atrial pressure was 20 mm Hg with a left atrial pressure of 8 to 10 mm Hg. Bypass was readily discontinued following implantation of the RVAP. Recovery of the patient's right ventricle was evaluated with serial determinations of right ventricular work. The RVAP was removed on the fifth postoperative day and the patient made a complete recovery. Postoperatively, gated radionuclide angiography demonstrated moderate recovery of right ventricular function. We suspect that the perioperative right ventricular failure was a result of unsatisfactory myocardial protection due to total occlusion of the proximal right coronary artery, which resulted in a maldistribution of the cardioplegic solution. This case demonstrates that right ventricular function can be restored following circulatory support with a mechanical assist device.

Coarctation in Taussig-Bing malformation of the heart. Surgical significance.

In a review of 126 heart specimens of simple complete transposition of the great arteries with ventricular septal defect (VSD), coarctation was noted in eight (6%). In 105 Taussig-Bing heart specimens, coarctation and/or aortic outflow tract obstruction was noted in 56 (53%) (p less than 10(-10). This was similar to our surgical experience in 26 patients with transposition and VSD or Taussig-Bing heart. Six of nine patients with Taussig-Bing heart also had coarctation of the aorta, whereas all 17 patients with transposition and VSD had a normal aorta. Four patients with Taussig-Bing heart underwent coarctation repair and pulmonary artery banding at 2 to 7 days of age. The remaining two patients with Taussig-Bing heart did not have a hemodynamically significant coarctation. Five of the six patients with Taussig-Bing heart and coarctation underwent a Senning procedure between the ages of 7 weeks and 3 1/2 years. In four (all less than 4 months of age) the VSD could not be closed through the tricuspid valve. A right ventriculotomy was done in two and contributed to their deaths. In the other two patients the VSD was left alone and the pulmonary artery banded. Both remain well. The fifth child, aged 3 1/2 years, had the VSD closed through the tricuspid valve but died in the postoperative period of renal failure. The sixth patient is awaiting further operation following coarctation repair and pulmonary artery banding. We conclude that the presence of coarctation strongly suggests that Taussig-Bing heart malformation exists rather than transposition and VSD. Pulmonary artery banding and coarctation repair are the initial procedures of choice in the management of these critically ill newborn infants. Increasing cyanosis and failure to thrive will necessitate further operation. Closure of the VSD through the tricuspid valve in these infants is difficult. Pulmonary artery banding in association with a Senning procedure is preferable to a right ventriculotomy. Closure of the VSD is then planned at a later stage.

Anomalous mitral arcade: echocardiographic and angiographic recognition.

A patient with sudden onset of hemiplegia was noted to have an anomalous mitral arcade at cardiac surgery. Echocardiographic and angiographic data are correlated with the anatomic findings. The clinical significance of this anomaly is discussed.

Clinical effectiveness of mechanical ventricular bypass in treating postoperative heart failure.

Our group has designed an air-powered, sac-type ventricular assist pump (VAP) that has a smooth polyurethane surface and Bjork-Shiley-type valves. This VAP has undergone extensive testing in calves and has been available for clinical use during the last 5 years. When properly employed, the circulatory support permitted immediate separation of the patient from bypass. Definite hemodynamic evidence of improved ventricular function has been observed during the period of unloading of the deranged ventricle by the VAP. However, during the first 3 years of our experience, the VAP was used in 11 patients with 1 survivor. During the last 2 years, specific attention has been directed to use of right, left, or biventricular assistance as indicated, to prompt application of the VAP when required, and to use of atrial rather than ventricular cannulation for VAP inflow. Accordingly, the survival rate over this 2-year period has increased to 50% (four of eight patients). The short-term assist pump is an important adjuvant for the surgeon who operates on seriously ill cardiac patients.

Hetastarch as a prime for cardiopulmonary bypass.

Hetastarch, a synthetic colloid osmotic plasma volume expander, was employed in a prime for cardiopulmonary bypass in 37 patients undergoing myocardial revascularization. Comparison of laboratory values to those of 42 patients undergoing myocardial revascularization using an albumin-containing prime showed lower postoperative platelet counts (p less than 0.02) with hetastarch. There were no differences in chest tube drainage, blood use, plasma hemoglobin, fibrinogen levels, of coagulation times. The hetastarch prime cost $119.50 per patient, whereas the albumin-containing prime cost $321.35 per patient.

Comparative efficacy and tolerance of cefamandole and cephalothin as prophylaxis for open heart surgery: a randomized double-blind study.

Cephalothin, a common used agent for antimicrobial prophylaxis, was compared with cefamandole, a second generation semi-synthetic cephalosporin having a somewhat broader antimicrobial spectrum, in a randomized, double-blind clinical trial of 201 patients undergoing elective open heart surgery. Cephalothin was administered to 101 patients and 100 received cefamandole. The protocol was not followed in 23 patients, 11 of whom received cephalothin and 12 cefamandole. Of 90 patients who could be evaluated for efficacy of cephalothin, two developed superficial wound infections and one developed an asymptomatic urinary tract infection. Five of 88 patients who received cefamandole developed infections; urinary tract infections in two, mediastinitis in one, a superficial wound infection in one, and pneumonia in one after prolonged endotracheal ventilation. Both were well tolerated with no adverse reactions attributed to either antibiotic. Cephalothin and cefamandole appear to provide similar efficacy and patient tolerance in open heart surgery; however, the drug regimen for cefamandole cost $83, whereas it was $58 for cephalothin.