Influence of age-specific lung function on survival after coronary bypass.

BACKGROUND: Respiratory complications after successful coronary artery bypass grafting influence the immediate recovery of a patient; however, whether they influence the longevity of a patient is largely unknown. The aim of this study was to examine the effects of preoperative pulmonary risk factors in younger patients and older patients on outcome after coronary artery bypass grafting. METHODS: A retrospective chart review was performed on 939 patients who underwent primary coronary artery bypass grafting between July 1987 and November 1996. For better comparison, they were arbitrarily divided by age into two groups: group 1, less than 70 years old (n = 710), and group 2, 70 years old or older (n = 229). The variables collected for each patient included history of chronic obstructive pulmonary disease, active smoking, forced expiratory volume, and ventilatory support for more than 48 hours. These variables were compared with postoperative length of stay in the intensive care unit, length of stay in the hospital, and the midterm survival up to 5 years. The data were analyzed by the use of univariate/multivariate log-rank tests and the method of Kaplan-Meier survival estimates. RESULTS: The presence of chronic obstructive pulmonary disease was associated with increased length of stay in the intensive care unit and in the hospital for both groups. Preoperative forced expiratory volume in 1 second, significantly affected length of stay in the hospital only in the patients less than 70 years old (p = 0.0001). Delayed extubation beyond 48 hours of ventilatory support resulted in prolonged length of stay in the intensive care unit and in the hospital for patients less than 70 years old (p = 0.0001, p = 0.0001, respectively) and patients 70 years old or older (p = 0.0001, p = 0.0001, respectively). The 5-year survival after coronary artery bypass grafting for both groups was significantly influenced by the level of preoperative forced expiratory volume in 1 second (p = 0.0004, p = 0.0282, respectively). CONCLUSIONS: Patients with chronic obstructive pulmonary disease, irrespective of age, stay in the intensive care unit and in the hospital longer after coronary artery bypass grafting. In addition, preoperative forced expiratory volume in 1 second is a significant predictor of 5-year survival in the young and aged individuals undergoing coronary artery bypass grafting.

Long-term survival benefit of internal thoracic artery grafting is negligible in a patient with bad ventricle.

BACKGROUND: Although the internal thoracic artery (ITA) graft is well known for its benefit of enhancing patient longevity after coronary artery bypass grafting (CABG), whether its superior patency is associated with improved patient survival at all levels of left ventricular function is unknown. The purpose of this study was to determine whether the use of ITA grafting during CABG confers improved survival benefit to patients with impaired preoperative left ventricular function. METHODS: A retrospective chart review was performed in 966 patients who had undergone isolated primary CABG between 1984 and 1995. The study population included 320 patients with only venous conduits (no-ITA group) and 646 patients with at least one ITA conduit (ITA group). A Cox partial likelihood approach was used to model the instantaneous mortality risk ratios as functions of ITA use and preoperative ejection fraction (EF). The forward stepwise regression model specifically examined the following potential confounders in the risk analyses: year of operation, patient age, weight, body surface area, graft location, number of grafts, perfusion time, ischemia time and Veterans Administration preoperative cardiac surgical risk estimates. RESULTS: Early (30-day) mortality in the ITA group (0.5%) was lower than the no-ITA group (4.1%) (p=0.0004). While 91% of the ITA group patients were still alive, only 70% of the no-ITA group patients were long-term survivors (p=0.0001). The ITA risk ratios for the increasing proportions of EF were not the same. In patients with E<0.40, the ITA risk ratio, 2.96, was significantly different (p=0.0001). It was only for EF >0.46, a significant survival benefit due to an ITA graft could be detected. The ITA-EF relationship was not confounded by the inclusion of those potential confounding variables in the model. CONCLUSIONS: Patient survival after CABG using an ITA graft may be affected by the level of preoperative EF. The internal thoracic artery-specific patient survival benefit appears to be less in a patient with poor left ventricular function.

Influence of increasing age on long-term survival after coronary artery bypass grafting.

BACKGROUND: Despite the steady increase in the number of elderly patients undergoing coronary artery bypass grafting (CABG), skepticism still exists as to whether this operation is justified in older people with a reduced life expectancy. The purpose of this study was to examine the effects of increasing age on outcome after CABG. METHODS: A retrospective chart review was performed on 1,689 consecutive veterans of the United States Armed Forces undergoing isolated primary CABG from January 1972 through December 1994. For better comparison, they were arbitrarily divided by age into three groups: group I, 50 years of age or less (n = 213), group II, between 51 and 70 years of age (n = 1,258), and group III, more than 70 years of age (n = 218). Long-term survival for each group was compared to that of their age-matched population derived from Wisconsin life tables. RESULTS: The preoperative ejection fraction was comparable in all three groups (p = 0.114). The patients older than 70 years of age had received more grafts per operation than the patients 50 years of age and younger (3.7 versus 3.3) (p = 0.0001). Although the aortic cross-clamp time was prolonged with advanced age (p = 0.0002), the cardiopulmonary perfusion time was shortest in elderly patients (p = 0.0001). The early (30-day) mortality for the entire study population was 1.3%. There was a linear correlation between increasing age and early (30-day) mortality: group I, 0.5% (1/213); group II, 1.0% (13/1,258); and group III, 3.2% (7/218). The overall 10-year actuarial survival for all patients was 67%. The 10-year survival was diminished with increasing age (p = 0.0001): 74% for group I, 68% for group II, and 47% for group III. Comparative analysis of the three groups with their age-matched counterparts demonstrated an age-related survival after CABG. In group I, reduced survival was evident 4 years after the CABG: the 10-year survival in group I was 74.2%, and the survival of their age-matched population was 93.4% (confidence interval, 67% to 81.9%). In group II a survival difference was obvious 8 years after CABG: 10-year survival of 67.5% versus 75.1% in their age-matched population (confidence interval, 64.8% to 71.6%). In the elderly group of patients, no survival difference was noted: 10-year survival of 42.7% versus 45.9% of the age-matched population (confidence interval, 29.8% to 64.6%). CONCLUSIONS: An acceptable early mortality and long-term survival equal to those seen for an age-matched elderly population are sound outcome measures that support the justification of CABG in older patients irrespective of age.

Exposing the circumflex coronary artery: the heartflip technique.

A method to expose the circumflex coronary artery in its course in the atrioventricular groove is introduced. No special equipment or assistance is required. This method also can be applied to expose the obtuse marginal branches of the circumflex coronary artery. Adverse effects have not been observed.

The effects of intraoperative autologous whole blood sequestration on the need for transfusion of allogenic blood and blood products in coronary bypass operations.

We investigated the effect of intraoperative autologous blood sequestration (IABS), an old blood conservation method, on transfusion requirements for homologous packed red blood cells (PRBC), platelets, and fresh frozen plasma (FFP) for patients undergoing coronary bypass surgery. This non-randomized retrospective study involved 204 patients who underwent isolated primary coronary artery bypass grafting (CABG). In 140 patients (IABS Group), autologous heparinized whole blood was removed intraoperatively via aortic cannula before bypass and retransfused at the conclusion of extracorporeal circulation. In 64 control patients, no IABS was performed. Demographic characteristics and operative and perioperative variables for both groups were similar (p > 0.05). In 140 patients, the mean sequestered blood volume was 1430 ml (range = 700-2100 ml). The banked PRBC requirement during hospitalization was 1.91 units in the No IABS Group and 2.25 units for the IABS Group (p = 0.2957). The need for platelet transfusion was 3.06 units in the No IABS Group and 1.09 units in the IABS Group (p = 0.0003). In the No IABS Group, 1.31 units of FFP was transfused and in the IABS Group, 0.49 units was transfused (p = 0.0004). To identify possible confounding factors, we performed a multivariate Poisson regression analysis for the 22 patient variables by a forward stepwise procedure. Regression analysis indicated that IABS did not alter the need for PRBC transfusion (p = 0.6194) but adjusted differences did confirm that IABS was associated with decreased need for transfusion of platelets and FFP (p = 0.0001 and p = 0.0002, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative study of cefazolin, cefamandole, and vancomycin for surgical prophylaxis in cardiac and vascular operations. A double-blind randomized trial.

Three-hundred twenty-one adults undergoing cardiac or major vascular operations were randomized to receive intravenous cefazolin, cefamandole, or vancomycin for prophylaxis against surgical infection in a double-blind trial. All three regimens provided therapeutic blood levels throughout operation in patients studied undergoing cardiopulmonary bypass. The prevalence of surgical wound infection was lowest with vancomycin (4 infections [3.7%] versus 14 [12.3%] and 13 [11.5%] in the cefazolin and cefamandole groups, respectively; p = 0.05); there were no thoracic wound infections in cardiac operations in the vancomycin group (p = 0.04). The mean duration of postoperative hospitalization was lowest in the vancomycin group (10.1 days; p < 0.01) and highest in the cefazolin group (12.9 days). Prophylaxis with vancomycin or cefamandole, compared with cefazolin, did not prevent nosocomial cutaneous colonization by methicillin-resistant coagulase-negative staphylococci; colonization or infection with vancomycin-resistant staphylococci or enterococci was not detected. Adverse effects attributable to the prophylactic regimen were infrequent in all three groups. Eight patients given vancomycin became hypotensive during administration of a dose, despite infusion during a 1-hour period; however, slowing the rate of administration and pretreating with diphenhydramine allowed vancomycin to be resumed and prophylaxis completed uneventfully in five of the patients. We conclude that administration of vancomycin (approximately 15 mg/kg), immediately preoperatively, provides therapeutic blood levels for surgical prophylaxis throughout most cardiac and vascular operations, resulting in protection against postoperative infection superior to that obtained with cefazolin or cefamandole. Vancomycin deserves consideration for inclusion in the prophylactic regimen (1) for prosthetic valve replacement and prosthetic vascular graft implantation, to reduce the risk of implant infection by methicillin-resistant coagulase-negative staphylococci and enterococci; (2) for any cardiovascular operation if the patient has recently received broad-spectrum antimicrobial therapy; and (3) for all cardiovascular operations in centers with a high prevalence of surgical infection with methicillin-resistant staphylococci or enterococci. Guidelines for dosing and administration of vancomycin for cardiovascular surgical prophylaxis are provided.

Milk of calcium pericardial effusion: case report.

A patient with milk of calcium (MOC) pericardial fluid secondary to radiation therapy is presented. We have been unable to identify a previous report of MOC pericardial fluid.

Five-year changes in coronary arteries of medical and surgical patients of the Veterans Administration Randomized Study of Bypass Surgery.

Progression of coronary artery disease was evaluated after 5 years of follow-up in 119 medically and 109 surgically treated randomized patients who adhered to their assigned therapy. Progression was defined as the appearance of a new lesion (greater than or equal to 50% stenosis) or worsening of a preexisting lesion in a coronary artery. Progression occurred in 36% (97 of 268) of the arteries in medical patients, in 38% (35 of 93) of the ungrafted arteries in surgical patients, in 74% (72 of 97) of the arteries with patent grafts at 5 years, and in 63% (29 of 46) of the arteries with closed grafts. After adjustment for the vessel system and the severity of disease at baseline, the risk of progression was three to six times higher in grafted arteries than in ungrafted arteries (p less than 0.01). For grafted arteries, the risk of progression was twice as high in arteries with patent grafts compared with those with closed grafts (p = 0.14). The majority (78%) of the progression in grafted arteries was to 100% occlusion. Proximal and distal progression rates in arteries with patent grafts were 74% and 11%, respectively. In the majority of arteries with closed grafts that progressed, the site of progression could not be determined. Regardless of treatment, the risk of progression was two times higher in the right coronary artery than in the left anterior descending or circumflex arteries. Progression risk was also twice as high in arteries with moderate disease at baseline compared with those with minimal or severe disease.

Comparison of survival in cardiac surgery at a Veterans Administration hospital and its affiliated university hospital.

Survival data were reviewed for 3330 open cardiac procedures from 1975 through 1984 at the William S. Middleton Memorial Veterans Hospital, Madison, Wis, and the University of Wisconsin Hospitals and Clinics, Madison. Respective operative survivals were 98.6% and 98.7% for myocardial revascularizations with vein graft or internal mammary artery (CABG), 96.2% and 96.8% for CABG reoperation, 97.8% and 95.9% for aortic valve replacement, 96.3% and 90.3% for aortic valve replacement plus CABG, 100.0% and 94.9% for mitral valve replacement, and 100.0% and 82.9% for mitral valve replacement plus CABG. There were no significant differences in six-year survival curves between hospitals despite threefold differences in average annual caseload (88 vs 294). This suggest that residency-directed cardiac surgery programs can function equally as well at a Veterans Administration hospital as at an affiliated university hospital.

Quantitation of absolute flow in coronary artery bypass grafts using digital subtraction angiography.

Coronary angiography defines the location and size of obstructive lesions, but does not assess their physiological significance. To assess a new method to measure the blood-flow waveform, reversed saphenous vein grafts from the left subclavian artery to the left anterior descending coronary artery were placed in five mongrel dogs. Contrast material was injected selectively into the vein graft while obtaining fluoroscopic images from AP and 45 degrees LAO projections. Blood flow was measured under baseline, low-flow, and hyperemic conditions using an electromagnetic flow probe (EM). Seventeen radiographic determinations of mean blood flow (range 18-130 ml/min) were linearly correlated to simultaneous EM measurements (r = 0.91 and 0.88, respectively). Contrast material injections changed EM flow measurements by an average of 35%, which though large, is less than with other radiographic methods. The computed blood-flow waveforms had a time resolution of 1/30 sec and were in good agreement with EM waveforms measured simultaneously. Clinical application of this radiographic method for determining the blood-flow waveform may allow early prediction of coronary artery bypass graft closure.

The fate of aortic valve homografts 12 to 17 years after implantation.

Results of long-term follow-up of an early cohort of patients receiving aortic valve homografts for aortic stenosis and aortic insufficiency are presented. All patients were operated upon by a single surgeon from 1966 to 1971. Eighty-three patients underwent insertion of 85 homograft aortic valves. Homografts were sterilized with either betapropiolactone (39 valves) or gamma irradiation (41 valves) and were inserted following storage in nutrient medium (16 valves) or after cryopreservation (51 valves). All homograft valves were sutured in the subcoronary position using a freehand technique. There was a 55 percent 15-year actuarial patient survival and a 16 percent 15-year actuarial homograft survival in this cohort. Homograft valve failure occurred gradually allowing the patients to be observed until they developed hemodynamic compromise at which time elective valve replacement was performed.

Catheter drainage of the pericardium. Practical method to maintain long-term patency.

Pericardiocentesis with catheter insertion and drainage is widely used in management of large pericardial effusions and cardiac tamponade. Two potential problems with an indwelling pericardial catheter system are catheter blockage and infection. We have utilized slow infusion of heparinized saline solution (3 ml/hr) via a continuous flush device to maintain catheter patency for up to seven days (mean 3.6) in 16 patients. Pericardial effusions were secondary to malignancy, uremia, and cardiac surgery. This article describes practical aspects of the technique. Most pericardial effusions can be successfully treated with pericardiocentesis and catheter drainage, provided the drainage is continued reliably and safely for several days. Surgical treatment such as subxiphoid pericardiostomy or partial pericardiectomy should be reserved for loculated effusions, clotted blood, subacute effusive-constrictive pericarditis, or significant recurrences after initial drainage.

Is milking and stripping chest tubes really necessary?

The purpose of this study was to determine if chest tubes that are not milked or stripped occlude more frequently than milked or stripped tubes, and if the amount of drainage varies according to the treatment of the tubes. Following coronary artery bypass graft procedures, 49 male subjects had their chest tubes milked every 2 hours, had them stripped every 2 hours, or served as controls (i.e., their tubes were neither milked nor stripped). An analysis of variance was applied to the results. There was no significant difference in total drainage volume, hourly zero drainage, heart rate, or occurrence of arrhythmias among the three groups of subjects. Four to 16 hours postoperatively, a significantly higher volume of drainage occurred in the subjects whose chest tubes had been stripped. Stripping is particularly discouraged during this interval. The chest tubes remained patent with or without milking or stripping. We conclude that neither milking nor stripping is necessary for the proper care of chest tubes. We recommend that tubes be positioned such that they promote continuous drainage.

Ectothermic philosophy of acid-base balance to prevent fibrillation during hypothermia.

In the ectotherms, or cold-blooded animals, carbon dioxide pressure decreases (PCO2) and pH increases as body temperature falls. This tends to increase coronary blood flow and prevent fibrillation. This concept was investigated in 181 consecutive patients undergoing open heart surgery of all types. In 121 cases, endothermic (warm-blooded) temperature-corrected normal values of pH, PCO2, and oxygen pressure were maintained during extracorporeal circulation as the perfusate temperature was lowered to 24 degrees C prior to aortic cross-clamping and administration of blood cardioplegia solution. In 49 patients (40%), ventricular fibrillation occurred prior to cross-clamping. In the other 60 consecutive cases, in which the ectothermic principle of cooling was applied, the PCO2 was allowed to decrease from 50 to 40 mm Hg and the non-temperature-corrected pH rose from 7.28 to 7.42. Fibrillation occurred in only 12 (20%) of these 60 patients.

Multiple calcified thrombi (rocks) in the right ventricle.

Large, organized right ventricular thrombi are rare. This report describes a 51 year old man with a history of recurrent pulmonary emboli treated with inferior vena cava ligation who subsequently developed multiple mobile calcified thrombi in the right ventricle. He was treated successfully by surgical resection. Unusual clinical presentation on admission consisted of a two component friction rub secondary to calcified masses rubbing against each other in systole and diastole. Cardiac catheterization showed a constrictive-restrictive pattern that persisted after surgery. The role of noninvasive studies in the diagnosis and long-term follow-up of the patient is emphasized.

Diagnosis and management of the hypothyroid patient with chest pain.

A retrospective analysis of 38 patients undergoing cardiac catheterization with the diagnoses of hypothyroidism and chest pain revealed 23 to be euthyroid while receiving replacement therapy and 15 to be hypothyroid. Cardiac index was significantly reduced (p less than 0.01) in hypothyroid and euthyroid patients with thyroxine values between 4 and 7 micrograms/dl (2.8 +/- 0.7 and 3.0 +/- 0.9 L/min/m2, respectively), compared to euthyroid patients with thyroxine values greater than 7 micrograms/dl with or without coronary artery disease (4.0 +/- 1.2 and 4.0 +/- 0.7 L/min/m2, respectively). Ten hypothyroid patients underwent coronary artery bypass. There were no deaths, and only one patient required prolonged postoperative intubation. With a mean follow-up of 36 months, there have been no myocardial infarctions and one late death, which occurred at 7 years secondary to stroke. We conclude that preoperative thyroid replacement therapy is theoretically dangerous and may not significantly improve hemodynamics until full replacement is achieved. Coronary bypass grafting can be performed safely despite hypothyroidism with excellent early results.

Digital subtraction angiography as a method of screening for coronary artery disease during peripheral vascular angiography.

Since myocardial infarction is the major cause of perioperative and postoperative death following peripheral vascular surgery, an accurate method of screening for coronary artery disease in this group of patients is needed. Digital subtraction angiography (DSA) with the use of intra-arterial aortic root injection of contrast material was evaluated as a method of screening for coronary artery disease in patients undergoing angiography for peripheral vascular disease. The feasibility of this method was demonstrated in animal experiments. Fifteen milliliters of Renografin-76 was power injected into the aortic root of seven anesthetized 20 kg mongrel dogs. Normal coronary artery anatomy was clearly demonstrated with DSA, and a series of iatrogenically created stenoses and occlusions were accurately identified. Excellent definition of patent grafts to the left anterior descending and circumflex coronary arteries was obtained in two dogs that had undergone previous coronary artery bypass grafting. A balloon occluder on one graft was used to demonstrate partial and near-total obstruction of the bypass graft. We are currently studying the use of aortic root injections using DSA to determine coronary artery disease in patients having standard angiography for peripheral vascular disease. Adequate visualization of coronary arteries and bypass grafts with only 20 ml of contrast has been obtained. The potential ability of this technique to identify and allow treatment of life-threatening coronary artery lesions in patients prior to or simultaneously with peripheral vascular surgery may result in reduced mortality.

Computerized fluoroscopy: new technique for the noninvasive evaluation of the aorta, coronary artery bypass grafts, and left ventricular function.

A computerized fluoroscopy system has been developed on the basis of real-time digital processing of x-ray transmission data from traditional image-intensified fluoroscopy equipment. High-quality visualization of any part of the arterial system is obtained following intravenous injection of 0.5 to 0.75 ml/kg of iodinated contrast materials. This report describes the use of this technique to evaluate the aortic arch, left ventricular function, and coronary artery bypass graft patency. Fifty intravenous studies were performed in 25 patients. Among 20 patients with coronary artery bypass grafts, computerized fluoroscopy correctly identified 11 of 15 patent grafts and 11 of 11 occluded grafts as confirmed by standard coronary arteriography in 11 of these patients. Unlike computerized tomography, our technique gives a longitudinal view of the bypass graft much like direct coronary angiography. Aortic arch studies included demonstration of a right aortic arch with a small left subclavian artery, a coarctation, and a normal aortic arch in a trauma patient with a wide mediastinum. Segmental wall motion abnormalities were clearly identified by a modification of the technique which produces a negative outline on the ventriculogram in dyskinetic segments. Ejection fractions may be calculated by determining the amount of iodine in the ventricle in systole and diastole. This technique may also be used to evaluate carotid disease and peripheral vascular disease in patients undergoing coronary artery bypass procedures. Computerized fluoroscopy, therefore, allows evaluation of the entire cardiovascular system by the relatively noninvasive technique of intravenous angiography.

Myocardial revascularization of the canine circumflex coronary artery using retrograde internal mammary artery flow without cardiopulmonary bypass.

A new surgical technique using perfusion of the circumflex coronary artery with retrograde blood flow of the internal mammary artery (IMA) is described. This project was undertaken because the IMA is uniquely well supplied with blood: proximally through is attachment to the subclavian artery, along the sternum by the intercostal arteries to the aorta, and distally from the iliac artery by the epigastric and musculophrenic arteries. In this experimental study, the IMA in 16 dogs was ligated and divided at the subclavian artery, then dissected free down along the sternum to obtain sufficient length. The large subclavian end was then anastomosed to the circumflex coronary artery using a metal cannula technique to perfuse the circumflex bed while the anastomosis was being done. In all 16 dogs, the retrograde flow of the IMA was adequate to maintain the circumflex bed. It is postulated that this technique may have some limited use in man.