Survival following fracture of strut from mitral prosthesis with disc translocation.

Mechanical complications of prosthetic valves are increasingly rare. The acute, catastrophic nature of the symptoms associated with massive transvalvular regurgitation preclude survival except with immediate operation. In the patient described herein, two weld fractures of a Björk-Shiley mitral prosthetic strut led to displacement of the valve occluder into the left atrium. The patient survived reoperation, following which the strut was detected radiologically in the left ventricular free wall. A slow, limited recovery resulted from his 5 preoperative hours of deep shock and coma. No complication attributable to the retained ventricular foreign body has been identified.

Influence of contractility on myocardial water distribution during cardiopulmonary bypass.

Water equilibrium within heart muscle during cardiopulmonary bypass is an important aspect of ventricular physiology which must be considered in efforts to optimize myocardial protection. This study focuses on the influence of the inotropic state of the ventricle in determining the amount of heart water and its regional distribution within the free wall of the left ventricle. Experiments involving cardiopulmonary bypass were performed in 57 dogs. Three spontaneous levels of myocardial contractility were identified under conditions of standard preload, afterload, and heart rate. Each increase in level (grade) was associated with a significantly higher myocardial wet weight/drug weight (W/D) ratio. In addition, higher levels of contractility were associated with a marked shift in water distribution within the left ventricular wall; water tended to accumulate in the inner half of the better contracting left ventricular wall, the reverse of the distribution seen at lower levels of contractility. These three grades of contractility and myocardial water content were not associated with any significant differences in total or regional myocardial blood flow, as determined by the use off radioactive microspheres. Maintenance of low levels of contractility during cardiopulmonary bypass may be desirable in order to prevent the occurrence of subendocardial edema.

The influence of prearrest factors on the preservation of left ventricular function during cardiopulmonary bypass.

Uniformly excellent myocardial protection during global ischemia in cardiac procedures requiring cessation of aortic root perfusion remains an elusive goal. This study establishes the importance of the preischemic inotropic state of the left ventricle and the arterial blood glucose concentration ([glucose]) immediately prior to an elective period of myocardial ischemia. Thirty-one experiments were performed on dogs subjected to 90 minutes of global ischemia on cardiopulmonary bypass at 28 degrees C with perfusion pressure constantly maintained at 90 mm Hg. The maximum rate of development of left ventricular pressure (LVdp/dtmax) at constant arterial and left atrial (LAP) pressures was used as a measure of contractility prior to ischemia. In a group of 18 of these dogs undergoing anoxic cardiac arrest, arterial blood [glucose], in conjunction with the preischemic LVdp/dtmax and the cross-clamp to asystole time interval (metabolic supply/demand index), significantly predicted (p less than 0.01) the functional result following the standard ischemic insult. In 13 other dogs with [glucose] greater than 120 mg/100 ml and treated with potassium cardioplegia, "normal" preischemic LVdp/dtmas (N = 7) was associated with a good functional result, but an elevated preischemic LVdp/dtmax (N = 6) produced severe functional impairment following ischemia. Optimum myocardial protection thus involves minimizing metabolic demands and maximizing metabolic supply immediately prior to and during the period of aortic cross-clamping.

Cannulation of the proximal aorta during long-term membrane lung perfusion.

Prolonged extracorporeal oxygenator support for acute respiratory failure is a clinical reality. Recent experience with 4 patients has demonstrated an advantage in delivery of saturated blood to the root of the aorta during venoarterial (VA) bypass. We have been able to perfuse the heart and bilateral cerebral hemispheres by advancing the tip of a large perfusion cannula to the aortic root from the common femoral artery. When the catheter did not pass beyond the transverse aortic arch, there was marked asymmetry of oxygenator perfusion, as determined by differential oxygen tension in right and left radial artery blood and by xenon-133 scans following isotope injection into the arterial return line. Long-term VA bypass lasting from 5 to 11 days resulted in long-term survival in 2 patients with post-traumatic gram-negative pneumonitis. The other patients, who had viral pneumonitis and post-transfusion respiratory failure, died after 9 and 11 days of membrane oxygenator support. No embolic lesions or arterial or valvular injuries were discovered at autopsy. This is a safe and useful method of providing oxygenated blood to the aortic root for equal distribution to the rest of the body.

The effect of antithrombotic therapy on patency rates of saphenous vein coronary artery bypass grafts.

In an attempt to improve upon the reported long-term patency rates of 65% to 85% for saphenous vein coronary artery bypass grafts (CABG), a prospective randomized trial comparing warfarin, aspirin, and placebo treatment in post-CABG patients was carried out. From an initial group of 216 patients, 161 patients remained in the study, and vein graft patency was determined in 111 patients (220 grafts) from 1 to 47 months postoperatively. There was a trend toward better cumulative graft patency in patients given warfarin, but the results did not achieve statistical significance. Improved results with warfarin were most marked among patients who were restudied within 24 months of CABG operation, in most instances because of the development of recurrent angina pectoris. There were four major bleeding complications of warfarin therapy, including one death, over 2,108 patient-months. Since most of the occlusive changes in vein grafts appear in the first 6 to 12 months, any effect of antithrombotic therapy will be most evident in the early postoperative period, with greatly reduced impact with long-term administration. Results of this study suggest that short-term antithrombotic therapy deserves further assessment in prevention of vein graft occlusion in the first year or two following a CABG operation. This potential benefit must be evaluated in the context of the recognized bleeding complications of warfarin therapy.

Cephalothin prophylaxis in cardiac valve surgery. A prospective, double-blind comparison of two-day and six-day regimens.

A prospective, double-blind study comparing a 6 day with a 2 day regimen of cephalothin prophylaxis was conducted among 200 patients undergoing prosthetic valve replacement. No cases of endocarditis occurred during the 2 month follow-up. Sternal wound infection developed in 2.8 per cent of the 6 day group and 2.1 per cent of the 2 day group. Pneumonia developed in 8.5 per cent of the 6 day and 5.3 per cent of the 2 day group; most of the bacteria isolated were susceptible to cephalothin. Urinary tract infection developed more frequently in the 2 day group (17.0 versus 8.5 per cent), particularly during the first 6 postoperative days. Three of 11 patients with no detectable cephalothin in their sera at the close of operation developed staphylococcal wound infections, compared with 2 of 175 patients whose sera contained cephalothin at the close of surgery (p = 0.002, Fisher's exact test). A short course of prophylactic antibiotics is prudent, but there is no justification for prolonging their administration.

Effect of cross-clamp time, temperature, and cardioplegic agents on myocardial function after induced arrest.

To evaluate the importance of time, temperature, and cardioplegia on the ability of the canine myocardium to maintain functional and ultrastructural integrity following induced arrest, we studied 220 dogs by varying myocardial temperature (34 degrees, 24 degrees, and 11 degrees C.), arrest time (0 to 120 minutes), and cardioplegic agents. Change in left ventricular function (LVF) was defined as the arithmetic difference in the center of mass between prearrest and postarrest LVF curves and was expressed as percent recovery of left ventricular stroke work. Left ventricular biopsies were obtained for semiquantitative electron microscopic analysis. After 90 minutes of cross-clamping, only hearts protected with combined hypothermia (H) and potassium-induced cardioplegia (K) significantly recovered prearrest function (24 degrees C.--80 percent, 11 degrees C.--99 percent). Hypothermia (H) alone for 90 minutes was less protective (24 degrees C.--49 percent, 11 degrees C.--59 percent). H preserved 84 percent of function after 60 minutes and 91 percent after 45 minutes. Normothermic arrest resulted in only 39 percent return of function at 45 minutes but could be extended with potassium-induced cardioplegia(K) to 78 percent at 60 minutes and 54 percent at 90 minutes. The addition of procaine plus HK improved protection over HK alone (95 percent versus 80 percent) but by itself was not effective. Neither hydrocortisone nor pretreatment with glucose-insulin-potassium, branched chain amino acids, or propranolol increased the protective effect of HK plus procaine. Inadequately protected groups (normothermia or H without K) showed more myocytic and capillary endothelial damage than the HK groups. No technique of myocardial protection studied completely preserved LVF, but the combination of HK plus procaine resulted in maximal recovery of LVF following cross-clamping for up to 120 minutes.

Vertebral arteriovenous fistulas following insertion of central monitoring catheters.

Iatrogenic vertebral arteriovenous fistulas were first reported in 1963. Since then, 20 additional cases have been reported--all following angiographic procedures. We report herein the first recognized cases of such fistulas resulting from percutaneous internal jugular and subclavian venous catheterizations performed for routine hemodynamic monitoring. The symptoms of late-occurring cervical bruit and thrill were identical to those described previously, although the ability to obliterate the thrill by pressure on the common carotid artery in one patient was inconsistent with other experience. These two patients were treated by direct ligation of the fistulous communication, after careful preoperative localization by angiography. Both patients have had complete disappearance of the symptoms and signs of the fistulas.

Sternal traction after open heart operation: an effective alternative to delayed sternal closure.

BACKGROUND: Routine closure of the sternum after cardiovascular surgical procedures sometimes causes severe cardiac depression because of a tamponade-like reduction in ventricular filling, leading to cardiogenic shock. Leaving the sternal halves apart, sealing the mediastinum by simply approximating the skin or using a prosthetic patch, and then performing delayed sternal closure in several days is a widely practiced life-saving maneuver. METHODS: Described herein is an experience with 5 patients with severe cardiac output depression of the type usually treated by delayed sternal closure. Instead, upward (outward) traction was applied to the anterior chest while the sternum was primarily closed. Traction was maintained with full-thickness chest wall sutures. RESULTS: The traction sutures were removed successfully in the intensive care unit between 1 and 4 days postoperatively, after appropriate vigorous treatment of postbypass myocardial enlargement and pulmonary distention and edema. CONCLUSIONS: This method of sternal traction allows physiologic improvement equivalent to delayed sternal closure in some patients and obviates the need for returning to the operating room to close the sternum in the early postoperative period.

An improved retractor for cardiac and thoracic operations.

Several standard abdominal wall retractors have been modified to improve exposure at the extremes of thoracic and groin incisions and to enhance the efficiency and comfort of the assistant in supplying adequate visibility in these areas.

Life-threatening hemorrhage from inadvertent cervical arteriotomy.

Catastrophic hemorrhage followed accidental puncture of the carotid artery or its branches during attempted preoperative insertion of flow-directed balloon-tipped pulmonary artery catheters in 2 patients who underwent open cardiac procedures. Direct repair of two carotid artery lacerations was necessary in 1 patient; the second patient slowly resorbed a large extrapleural hematoma without surgical intervention. This experience suggests that patients experiencing such seemingly innocuous but potentially disastrous arterial injuries should not be heparinized, and that any procedure involving cardiopulmonary bypass should be postponed for several days to allow safe healing of the laceration.

Repair of inflammatory tracheoesophageal fistula.

Benign acquired tracheoesophageal fistula is uncommon. Erosin of the membranous wall of the trachea and the anterior esophageal wall by the high-pressure cuff on a tracheostomy tube, often against the anvil of a nasogastric tube, may produce such fistulas. Techniques for closure have included patching the tracheal defect with muscle and, often, multiple staged procedures, planned or unplanned. Since any cuff lesion severe enough to cause a fistula necessarily damages the trachea circumferentially at the same level, definitive correction must include circumferential tracheal resection as well as closure of the fitstula. Five patients with tracheoesophageal fistula due to cuff perforation had repair by such a single-stage procedure. Through an anterior approach the involved trachea was resected, primary anastomosis was done, and the esophagus was closed in layers. In 3 of these 5 patients muscle was interposed for added security. One patient had undergone a prior attempt at repair elsewhere. One required a second resection of trachea for subsequent stomal stenosis. Repair in 2 additional patients with fistulas of complex origin related to direct trauma, sepsis, and foreign body involved adaptation of the basic technique to the special problem; 1 of these procedures was necessarily staged. Results in all 7 patients have been good.

Effect of induction and reperfusion with warm substrate-enriched cardioplegia on ventricular function.

BACKGROUND: This study tested the hypothesis that induction and reperfusion with warm substrate-enriched (IRWSE) blood cardioplegia improves postoperative left ventricular (LV) function in patients undergoing elective coronary bypass surgery (CABG). METHODS: After giving informed consent, 67 patients scheduled for CABG surgery were randomized to either IRWSE + cold blood (CB) or CB alone. IRWSE cardioplegia consisted of 37 degrees C substrate-enriched (glutamate, aspartate, hyperkalemic) anterograde and retrograde blood cardioplegic solution followed by non-substrate-enriched cardioplegic solution given at 4 degrees C to 8 degrees C. LV function was measured with ventriculograms, volume conductance catheters, echocardiography, and multiple gated (image) acquisition. RESULTS: The end-systolic pressure-volume relationship was improved postbypass in the IRWSE + CB group (CB, 1.5 +/- 0.74 mm Hg/mL vs IRWSE + CB, 2.1 +/- 1.2 mm Hg/mL; p = 0.042). The postoperative ejection fraction (EF%) was better preserved in the CB group (CB, 65 +/- 11.53% vs IRWSE + CB, 58.62 +/- 11.75%; p < 0.04). CONCLUSIONS: Our results demonstrate a transient improvement in LV systolic function in the immediate postbypass period in CABG patients in the IRWSE + CB group. The intraoperative benefits of the IRWSE + CB technique did not persist in the postoperative period.

Coronary artery bypass graft surgery: clinical decision making and cost-effectiveness analysis.

Decision-analytic techniques were used to evaluate the choice between an aortocoronary bypass operation and medical management in a set of hypothetical patients with coronary artery disease. The decision framework incorporates variables believed to have an important bearing on the choice of treatment. Probability estimates were obtained from two cardiologists and one cardiac surgeon. Patient preferences for the trade-off between years of survival and the quality of life as reflected by the severity of angina pectoris were made explicit by assigning utility values to alternative health outcomes. The results are expressed in terms of quality-adjusted years of life expectancy. Decision analysis favored operation for 13 of the 14 hypothetical patients, including patients with one- and two-vessel disease. The one patient for whom medical treatment was preferred had mild angina pectoris, severe left ventricular dysfunction, and a poor prognosis regardless of therapeutic modality. The results are sensitive to changes in the probability of long-term survival, but not to changes in operative mortality rates. In five patients, the physicians' clinical judgments favored medical treatment, whereas their decision-analysis-derived estimates of survival favored operation. Possible explanations for these discrepancies are discussed. A simplified cost-effectiveness analysis for patients in whom surgery was the optimal treatment indicated costs ranging from $1,500 to $250,000 per year of life gained and from $1,500 to $32,000 per quality-adjusted year of life gained.

Acute massive (pericardial effusive) pulmonary thromboembolism--pulmonary embolectomy revisited.

The most recent patient in a 13-year experience with 14 patients suffering massive pulmonary thromboembolism requiring pulmonary thromboembolectomy is the focus of this report. This 40-year-old woman not only survived life-threatening acute hypoxemia and right heart failure, but was also found to have developed a unique transudative 700 cc pericardial effusion. Pulmonary artery pressure was 90/30 (mean 50 mmHg), accompanied by 17 mm right ventricular alternans. Systemic alternans and tamponade physiology were absent. This unusual natural model for acute right heart failure illustrates a novel mechanism for pericardial effusion physiology.

Bioprosthetic endocarditis due to Cryptococcus neoformans.

Fungal prosthetic endocarditis continues to be a lethal complication of cardiac valve replacement. We describe a patient with culture-proved Cryptococcal endocarditis and myocarditis whose non-regurgitant xenograft aortic prosthesis was successfully replaced urgently upon the occurrence of new 1st degree A-V block in the third postoperative week. Operative intervention, including vigorous debridement of the aortic root, is effective in postoperative prosthetic fungal infections involving the myocardium. The patient described herein is now infection-free, with a non-regurgitant valve, one and one-half years following operation.