Cardiac valve surgery and myocardial damage: the role of cardiac troponin I.

AIM: The study investigated the release of cardiac Troponin I (cTnI) levels in heart valve surgery and in coronary artery bypass grafting (CABG). The aims of the research were 1) to evaluate the ability of cTnI to detect the myocardial damage; and 2) to demonstrate possible causative factors of the cTnI release after valve surgery. METHODS: A prospective, single-center study. Ninety consecutive patients were operated on for different types of cardiac surgery; 45 patients underwent cardiac valve surgery - The VALVE group. 45 patients underwent CABG surgery - the CABG group. CTnI levels were measured preoperatively, on the day of operation and the 7 days postoperatively. The diagnosis of damaged myocardium classically performed through the measurement of cTnI, twelve-lead electrocardiograms (ECG) and echocardiographics according to the protocol of the study. RESULTS: Although more elevated cTnI release was noticed in valve group early after operation, no occurrence of cardiac events was found in that group. Statistically significant occurrence of cardiac events was found in CABG group (P=0.015). No relationship was shown between the peak of cTnI and the presence of cardiac events in valve group. A statistically significant correlation was observed between cardiac events and peak cTnI in CABG group (P=0.05). Possible correlations were investigated between the peak of cTnI and perioperative parameters in both two groups. CONCLUSION: The absence of cardiac events and the association of valve surgery with higher early release of cTnI compared to CABG suggest that the type of surgery strongly affects the induction of myocardial damage.

Does hypothermic circulatory arrest or prolonged cardiopulmonary bypass time affect early outcome in reoperative aortic surgery?

AIM: Prolonged cardio-pulmonary bypass (CPB) time, usually necessary for reoperations, is known to increase mortality in coronary bypass procedures and aortic reoperations. We investigated if prolonged CPB time and arch reconstruction in reoperations of the thoracic aorta affect in-hospital outcome. METHODS: Twenty-nine patients underwent reoperations on the thoracic aorta. The reoperations performed were aortic root replacement with composite graft without aortic arch involvement in ten patients, isolated ascending aorta replacement in six patients, aortic arch replacement as a primary procedure in two patients, and aortic arch in conjunction with ascending or descending aorta replacement in 11 patients. RESULTS: Fourteen patients had aortic reoperation with deep hypothermic circulatory arrest (DHCA) and 15 without DHCA. The in-hospital mortality rate was 13.8%. The use deep hypothermic circulatory arrest or CPB time did not affect early outcome. Previous coronary artery bypass procedure was independent predictor of in-hospital mortality. Seven patients required re-exploration for bleeding. One patient suffered from stroke and finally five patients had prolonged ventilation, two requiring tracheostomy. There have been no deaths in the follow-up period. None of the patients has required repeat surgical intervention on the heart or the aorta. CONCLUSION: The use of DHCA or prolonged CPB time do not affect early outcome in reoperations of the thoracic aorta.

Pacemaker synchronization.

A method using the standard radio-frequency receiver was developed to telemeter biopotentials across the intact body Wall; it can be employed to program a stimulus to the heart at any phase of the cardiac cycle. The small variations of potential across the electrodes of the implanted cardiac pacemaker change the natural resonant frequency of the receiver in direct relation to the electrical activity of the heart.

Early mortality and morbidity of bilateral versus single internal thoracic artery revascularization: propensity and risk modeling.

OBJECTIVES: We examined whether bilateral internal thoracic artery (BITA) revascularization is associated with any increased in-hospital mortality and complications compared with single internal thoracic artery (SITA) revascularization. BACKGROUND: Despite proven long-term benefits, BITA revascularization has been slow to be adopted because of fear of increased early morbidity. METHODS: We evaluated 1,697 consecutive patients undergoing BITA (n = 867) or SITA (n = 830) revascularization. We used propensity score analyses and adjusted risk models to address differences between arms. RESULTS: There were 20 (2.3%) deaths in the BITA group versus 26 (3.1%) in the SITA group (odds ratio 0.73, p = 0.30). Propensity analysis identified several parameters that affected the decision to use BITA. Adjusting for propensity score and all potential risk factors, the odds ratio for death with BITA versus SITA was practically 1. Bilateral internal thoracic artery revascularization did not increase the number of in-hospital complications with the possible exception of deep sternal wound infections (11 [1.3%] vs. 3 [0.4%], p = 0.057). In multivariate modeling BITA increased the risk of deep sternal wound infections only in emergent cases and in older patients; the excess risk was negligible among 1,206 patients (71.1% of total) who did not have emergent revascularization and were < or =70 years old (risk difference 0.3%, p = 0.74). There was no difference in length of stay after adjustment for propensity factors (mean 11.3 vs. 11.7 days, p = 0.66). CONCLUSIONS: Bilateral internal thoracic artery revascularization grafting confers no increased risk for early death and does not prolong hospital stay. The small increase in the risk of deep sternal wound infections does not affect the majority of patients.

Cardiac rupture--challenge in diagnosis and management.

Previous studies of the incidence, natural history, pathogenesis and diagnosis of cardiac rupture are presented, and 20 additional cases described. Progressive cardiorrhexis after myocardial infarction causes death in possibly more than 25,000 persons a year in the United States, and more frequent antemortem diagnosis is needed. Suggestions for future clinical and experimental studies are described and possible means of early diagnosis and therapy are outlined.

Acute aortic arch dissection: reevaluation of the indications for medical and surgical therapy.

Of 42 patients with dissection of the aorta, 4 had important arch involvement. Results were good in 2 patients treated medically. In two other patients wrapping the arch with a Dacron graft successfully prevented fatal hemorrhage. This technique avoids the need for arch replacement in selected cases. From this experience and a review of others a flow sheet was developed to guide decision-making in the surgical and medical management of patients with aortic dissection.

Aneurysm of the body of the left atrium presenting with chest pain.

A patient with aneurysm of the body of the left atrium presenting with angina pectoris and mild congestive heart failure, but completely normal coronary arteriograms, is reported. A deverticulum seen in the left ventricular angiogram, read as a ventricular diverticulum, was found at surgery to be an aneurysm of the body of the left atrium. The possible etiologics and complications of the left atrial aneurysm are briefly discussed.

An unusual form of late stenosis after aortic valve replacement with a cloth-covered Starr-Edwards prosthesis.

A 24-year-old man presented with late stenosis of a cloth-covered Starr-Edwards valve (model 2320). Fibrous ingrowth occurred at the inflow orifice of the valve and all three struts were adherent to the aortic wall, creating a "tunnel" form of obstruction. The stenotic valve was replaced with a porcine heterograft, and the small aortic root was enlarged with a Dacron patch. This form of late prosthetic valve stenosis should have been prevented by enlargement of the aortic root at the time of valve insertion and by long-term anticoagulant therapy.

Earlier operation for left-sided Pseudomonas endocarditis in drug addicts.

Three consecutive patients with Pseudomonas endocarditis were treated by early operation with no deaths. The indications for operation were severe failure, systemic embolization, and infection refractory to antibiotics. The organism is aggressive, characterized by early invasion of the myocardium. Wide débridement of the anulus is necessary to remove any vegetations or intramyocardial abscessed wall. Because multiple valve infection is common, it is important to evaluate all four cardiac valves at the time of operation. Removing a second rim of the mitral anulus for separate culture at the time of mitral valve replacement may demonstrate the degree to which the valve resection has removed all infection. Early operation is necessary for reinfection of the prosthetic valve; however, metastatic abscess should also be considered in the face of continued signs of infection postoperatively. Patients should receive a 6 week postoperative course of antibiotics which have been shown by in vitro testing to be serum bactericidal in at least a 1:8 dilution. The operative findings of invasion of the myocardium by the organism and the surgical success in this small series have resulted in our recommending earlier operation in patients with these indications.

Parallel growth of rectus sheath grafts and recipient aorta. Critical role of graft tissue preservation.

Previous experimental studies revealed striking similarities in mechanical properties of host aortic tissue and rectus sheath inserted as an aortic graft, as well as enlargement of some of the grafts. We have now evaluated the capacity of rectus sheath grafts to keep pace with aortic growth and investigated the role of tissue preservation in determining the ability of such grafts to maintain suitable dimensions. Autologous rectus sheath grafts were substituted for thoracic aortic segments in 15 puppies, 8 weeks of age. Nine grafts were inserted with careful attention to tissue preservation (live grafts), but in six experiments, cells were killed and tissues fixed by freezing and thawing in acetone before graft implantation (devitalized grafts). Grafts were fixed in situ by controlled pressure perfusion and examined 1, 2, and 3 months after implantation. Over the 3 month experimental interval, body weight increased from 2.0 +/- 1 pounds to 25.0 +/- 2.5 pounds, and as is characteristic for the period of maximum growth rate for the animals. Total thoracic aortic length increased 41.2% +/- 6.1% and aortic diameter, 30.0% +/- 3.1%, during this time. Growth rate of the total thoracic aortic length during the first month was greater for the devitalized graft group, but aortic length was the same for both groups at 3 months. The live grafts increased 42.3% +/- 12.0% in length and 27.3% +/- 3.0% in diameter, i.e., to the same degree as the aorta, whereas the devitalized grafts showed only slight increases in length and diameter (2.1% +/- 2% and 5.3% +/- 5%, respectively). The live rectus sheath grafts were augmented and largely replaced by a newly formed, layered fibrocellular structure, 45.8 +/- 25.8 mm3 in volume, whereas in the devitalized grafts more of the original rectus sheath persisted and only a minimal amount of organized connective tissue sheath was formed (volume 18.7 +/- 8.9 mm3). In addition, cellularity was much greater in live grafts than in devitalized specimens (990.9 +/- 186.8 cells/mm2 and 423.6 +/- 124.7 cells/mm2, respectively). All of the grafts were lined by endothelium. These findings indicate that autologous rectus sheath aortic grafts may be used to provide channels which keep pace with aortic dimensions during the period of maximum growth, provided that the graft tissue is viable on implantation. Long-term durability of such grafts may also depend on tissue preservation.

Use of the pulmonary artery for left ventricular venting during cardiac operations.

Data relating to the hemodynamic efficaciousness and mechanism of action of a pulmonary artery catheter or vent used for left ventricular venting during cardiac operations are presented. The pulmonary artery vent is a plastic sump catheter that is introduced into the main pulmonary artery through a purse-string suture and connected via a roller pump to the venous reservoir of the heart-lung perfusion machine. Placement and removal require only a few minutes. The pulmonary artery vent retrieved 85% of a 99mtechnetium-labeled solution placed in the left atrium during aortic cross-clamping, and there was no detectable radioactivity in peripheral or aortic root blood samples. Pulmonary artery vent return during cardiopulmonary bypass in 10 patients undergoing coronary artery bypass averaged 12.5 L. The effectiveness of left ventricular decompression was evaluated in 20 patients also undergoing bypass grafting. Use of the pulmonary artery vent consistently and significantly decreased left heart pressures, compared to the control situation with the vent off, with the aortic cross-clamp applied, and in both the fibrillating and beating heart in the early postischemic reperfusion period. We reached the following conclusions: (1) The pulmonary artery vent withdraws left heart blood via the pulmonary vasculature, in addition to returning right heart spillover and retrieving bronchial flow. (2) Left heart pressures are reduced to levels which reduce oxygen demands and preserve endocardial perfusion, therefore protecting myocardium, during fibrillation and during coronary reperfusion of the beating heart. (3) Because of its effectiveness and safety, especially the impossibility of introducing air into the left ventricle, the pulmonary artery vent is recommended for routine left ventricular venting.

Autologous rectus sheath grafts. V. Growth in aortic grafts.

Experiments were designed to test autologous rectus sheath as a replacement for the thoracic aorta in the growing dog. Adequacy of graft function was determined by angiography at 4 month intervals; stress-strain measurements and microscopic examination were made at the time of autopsy. A 3 cm tubular graft of rectus sheath tissue was employed as an aortic graft in 13 mongrel puppies. Nine puppies (70%) were long-term survivors and were put to death between 6 and 22 months postoperatively. No deaths were due to graft failure. Angiographic studies demonstrated patency of the graft without development of pressure gradients. An increase in diameter of the aorta (21.25%) and the rectus sheath graft %22.87%) were demonstrated in all cases. During the time of observation, the compliance of the growing aorta (93,120 dynes/cm2) decreased to one fourth that of the control aortic tissue (24,800 dynes/cm2), whereas the compliance of the rectus sheath graft (547,1000 dynes/cm2) decreased to only one eighth that of the control rectus sheath (47,400 dynes/cm2). Tensile strength is maintained in both the growing aorta (4.5 x 10(7) dynes/cm2) and the rectus sheath graft (4.7 x 10(7) dynes/cm2; p less than 0.05). Microscopic examination showed no calcification, thinning, or weakness. Vascularization of the graft had occurred, with cellular proliferation and development of more than 30 lamellar-like units in the media and an adventitia-like surface.

Detection, prediction, and significance of perioperative myocardial infarction following aorta-coronary bypass.

One hundred consecutive patients undergoing aorta-coronary bypass grafting (ACBG) alone, without ventricular venting, were prospectively studied to determine the incidence and consequence of perioperative myocardial infarction (PMI) and the clinical variables that were predictive of PMI. Incidence was determined by serial electrocardiography (ECG) 100 patients; serum CK, GOT, and LDH (100 patients). CK isoenzymes (qualitative 100 patients, quantitated 50 patients); vectorcardiography (VCG) (78 patients); and 99mtechnetium pyrophosphate scintigraphy (TcPyp) (52 patients). The incidence of PMI by ECG was 9%; an additional 8% of cases was diagnosed by enzymes alone. The incidence of diagnostic change by VCG was 19% and by scintigraphy, 25%. Using at least one changed variable of the remaining three as the reference standard, the relative sensitivity and relative specificity of given variables in the diagnosis of PMI were as follows: ECG 67% and 100%, respectively; VCG 85% and 94%; scintigraphy 92% and 97%; and serum enzymes 86% and 96%. By univariate analysis, unstable angina was the only significant predictor of PMI. The operative mortality rate was 2% and the mortality rate at 12 months was 5%. There was a significantly greater mortality rate in patients with PMI diagnosed by ECG (p less than 0.01), in patients with unstable angina pectoris before operation (p less than 0.05), and in women (p less than 0.05).

Autologous whole plasma fibrin gel. Intraoperative procurement.

Fibrin glue is a relatively recent addition to the armamentarium of hemostatic agents for surgical use. Its efficacy has been repeatedly demonstrated in almost all surgical disciplines and subspecialties. Its use in the United States has been limited because of the risk of viral transmission associated with the use of human plasma. Previous authors have described techniques that limit this risk, but they are frequently impractical, expensive, or cumbersome. We describe the use of patients' own fresh plasma to make fibrin gel at the operative field. It provided hemostasis at least as good as that from heterologous plasma glue in 40 cardiac surgical patients. Autologous whole plasma fibrin gel is inexpensive and safe and eliminates the risk of viral transmission associated with glue derived from heterologous donor plasma.

Surface cooling (20 degrees C) and circulatory arrest in infants undergoing cardiac surgery. Results in ventricular septal defect, complete atrioventricular canal, and total anomalous pulmonary venous connection.

During a six-year period, 46 severely symptomatic infants (average age, 5.1 months) underwent correction of ventricular septal defect (22 patients), total anomalous pulmonary venous connection (13 patients), and complete atrioventricular canal (11 patients), with the use of surface cooling to 20 degrees C. Cardiac repair was performed during circulatory arrest, and rewarming was performed with a pump oxygenator. Ten patients undergoing repair of ventricular septal defects were studied hemodynamically at 21 degrees C, before repair and at 37 degrees C after rewarming. Heart rate, left ventricular systolic pressure, maximum dp/dt, cardiac index, stroke work, and oxygen consumption were reduced substantially at 21 degrees C. Systemic vascualr resistance was increased at 21 degrees C. All changes were reversible with repair and rewarming. A protocol for hemodilution and crystalloid volume loading was devised to maintain urine output after early patients were noted to demonstrate renal dysfunction. With this protocol, survival rates were 89% for patients with ventricular septal defects, 67% for those with atrioventricular canal defects, and 85% for those with total anomalous pulmonary-venous connection.

Complications of percutaneous intra-aortic balloon pump use in patients with peripheral vascular disease.

Percutaneous intra-aortic balloon pump use may carry an increased risk for patients with peripheral vascular disease. To determine the incidence and types of associated complications, the medical records of 144 patients who underwent a total of 153 percutaneous intra-aortic balloon pump insertions were reviewed. Patients were divided into two groups. Group 1 was composed of 20 patients with a history of peripheral vascular disease. Group 2 was composed of 124 patients without such history; they underwent a total of 133 insertions. Nineteen major complications (12%) occurred, 12 in group 1 (60% of 20 insertions) and seven in group 2 (5% of 133 insertions). Major complications were further classified by their nature: embolic, occlusive, and technical. All three types of complications occurred more frequently in group 1. Embolic complications occurred more frequently in patients with aneurysms and proved the most lethal, with two of six deaths in group 1 resulting from this complication.

The cardiac veins and retrograde coronary venous perfusion.

Study of retrograde coronary venous perfusion has been greatly overshadowed in the past decade by the advent and success of direct coronary artery revascularization. Recently there has been renewed interest in retrograde venous perfusion as a possible means of restoring myocardial circulation in selected patients. This paper reviews the anatomy and physiology of the cardiac venous system and the history of retrograde venous perfusion, with emphasis on recent experimental work and clinical trials involving retrograde coronary vein perfusion (RCVP).

A late complication of tuberculous pericarditis after partial pericardial resection.

Tuberculous pericarditis is estimated to occur in 1% to 2% of cases of pulmonary tuberculosis. Despite adequate therapy, a subset of patients may eventually require pericardiectomy. Incomplete pericardial resections are associated with an increased incidence of late complications. We report a cutaneous sinus tract communicating with residual pericardium and a retrosternal abscess cavity 11 years after partial pericardial resection.

Myocardial rupture: III. Chamber pressure, rate of distention, and ventricular disruption in isolated hearts.

We have developed an in vitro technique for producing myocardial rupture in lamb hearts, which relates tensile strength to a variety of conditions which can prevail in normal and infarcted human hearts. Retrograde perfusion of saline solution and inflation of the left ventricle was used to apply progressive stress to the left ventricular wall. Three separate sites of myocardial rupture were observed and occurred with the frequency of 54% at the papillary muscle, 30% at the interventricular septum, and 16% at the free wall of the left ventricle. The distribution and configuration of the experimental ruptures were similar to those usually noted as complications of human myocardial infarction. The mean rupturing pressure was 526 mm Hg in normal lamb hearts. Application of these techniques should ultimately provide data relevant to the diagnosis, prevention, and treatment of myocardial rupture.

Myocardial revascularization with the lateral costal artery.

The lateral costal artery is a branch of the internal mammary artery that occurs in 27% of cadaver series. The similarities to the internal mammary artery and its easy accessibility would suggest its use as a bypass conduit for coronary revascularization. We describe the harvesting and utilization of this artery as an in situ coronary bypass graft, and we have initiated a study examining the exact frequency of this anomalous vessel. The availability of the lateral costal artery either unilaterally or bilaterally adds another dimension to the concept of complete arterial conduit myocardial revascularization.