Impact of complications on outcomes following aortic and mitral valve replacements in the United States.

AIM: Heart valve replacement surgeries account for 20% of all cardiac procedures. In-hospital mortality rates are approximately 6% for aortic valve replacements and 10% for mitral valve replacements. The objectives of the study are to provide nationally representative estimates of complications following aortic and mitral valve replacements and to quantify the impact of different types of complications on in-hospital outcomes. METHODS: The Nationwide Inpatient Sample was analyzed for years 2000-2003. The effect of complications on in-hospital mortality, length of stay (LOS), and hospital charges were examined using bivariate and multivariable logistic and linear regression analyses. The confounding effects of age, sex, primary diagnosis, type of valve replacement, type of admission, comorbid conditions, and hospital characteristics were adjusted. RESULTS: A total of 43,909 patients underwent aortic valve replacement as the primary procedure during the study period and 16,516 patients underwent mitral valve replacement. Complications occurred in 35.2% of those undergoing aortic valve replacements and in 36.4% of those undergoing mitral valve replacements. Almost half of these are cardiac complications and a quarter involve hemorrhage/hematoma/seroma. Complications were significantly associated with in-hospital mortality, LOS, and hospital charges even after adjusting for patient and hospital characteristics. CONCLUSION: Complications are prevalent and exert a considerable influence on outcomes following aortic and mitral valve replacements. Quality initiatives should focus on minimizing complications and improving processes of care that would enable complications to be better resolved if they occur.

Safety of the right atrial approach for combined mitral and tricuspid valve procedures.

Patients undergoing operation for combined mitral and tricuspid valvular disease may have the repair performed through the right atrium and the interatrial septum. Although the transseptal method is an established procedure, recent reports have stressed the disadvantages of this operation and underscored the risk of the development of complete atrioventricular dissociation with this technique. A review of our results with this approach confirms the efficacy and safety of this method. The surgical protocols used are described.

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.

Bronchogenic carcinoma located in the aortic window. The importance of the primary lesion as a determinant of survival.

Thirty-four patients with an aortic window lesion were carefully staged with gallium scans and mediastinoscopy according to the TNM classification system for carcinoma of the lung. All were in Stage III. Twenty-five patients had non-oat cell carcinomas (15 squamous cell, eight adeno-, two large cell) and nine had oat cell carcinomas. Quantitative ventilation-perfusion lung scans were particularly helpful in verifying the subaortic location of the tumor by showing a less than 20% interference with pulmonary blood flow or ventilation secondary to left mainstem bronchus or pulmonary artery invasion. Decision for resectability in 13 Stage III M0 patients was based on the length of the uninvolved proximal left main pulmonary artery seen on pulmonary arteriogram. Eight patients (seven non-oat cell and one oat cell) had resection after radiation and prior to chemotherapy (after two cycles of chemotherapy and prior to radiation therapy for the oat cell) with a resultant survival rate better than those of M0 and M1 non-oat cell or oat cell patients without resection. The survival rates of nine non-oat cell M0 patients, nine non-oat cell M1 patients, and eight oat cell patients, all without resection, were not statistically different. This similarity in survival rates is explained by the observation that 38% of the non-oat cell M1, 71% of the non-oat cell M0, and 63% of the oat cell patients died from complications of their primary tumor. Patients with aortic window lesions, irrespective of their histology, have an extremely poor prognosis due to the high incidence of lethal complications of their primary tumor. Complete resection when feasible, as judged by pulmonary arteriography, provides the best control of the primary tumor and, as a consequence, gives longer survival.

Operation for diagnosis and treatment of pericardial effusions.

UNLABELLED: An experience with 32 consecutive patients with pericardial effusions is reviewed and presented. Malignant effusions: Twenty patients had underlying malignancy. Five had no symptoms, nine had ambiguous symptoms, and six had pericardial tamponade. Initial treatment in eight was pericardiocentesis, which provided diagnosis and treatment in one but was clinically unsuccessful in seven and caused right ventricular puncture in one. Subxiphoid pericardial window in 19 patients showed malignant involvement in six but documented a nonmalignant effusion in 13. There were no operative complications, and no effusions have recurred with long-term follow-up. Only two patients with true malignant effusions had significant long-term survival as compared with 11 of 13 with benign effusions. Uremic effusions: Six patients with renal failure required intervention, three for hemodynamic compromise and one for possible infection. Diagnostic pericardiocentesis documented a sterile effusion in one patient. Five patients had subxiphoid pericardial window without recurrence of effusion. One patient required reexploration for rectus muscle bleeding. Other effusions: All six patients had hemodynamic compromise. Pericardiocentesis was successful in three of four patients but effected resolution in none. Subxiphoid pericardial window was performed in all. The effusion recurred in a patient with periarteritis nodosa, and a patient with viral myocarditis developed a left ventricular pseudoaneurysm that required operation. CONCLUSIONS: Subxiphoid pericardial window provides definitive diagnosis and treatment for pericardial effusions of all causes with low morbidity rates whereas pericardiocentesis is safe but usually ineffective/unproductive; many effusions in patients with cancer are not related to malignant pericardial involvement and documentation is important for treatment planning.

A canine model to assess the electrical stability of the transplanted heart.

The electrophysiological stability of the transplanted heart under conditions of myocardial ischemia is largely unknown. This problem was studied using a canine model of total cardiac denervation as a substitute for transplantation. Group 1 (N = 3) served as control with placement of ventricular pacing wires only. Group 2 (N = 3) underwent total cardiac denervation with placement of ventricular wires. Group 3 (N = 8) underwent total cardiac denervation with subsequent ligation of the left anterior descending coronary artery and collaterals to the apex. Group 4 (N = 9) underwent coronary artery ligation only. Chronic electrophysiological studies were conducted in all groups in the conscious state. Electrophysiological variables were determined from continuous Holter monitoring of the ECG, determination of strength-interval curves, and assessment of the inducibility of ventricular tachycardia by premature programmed pacing. In general, the denervated, infarcted group (Group 3) consistently demonstrated a greater level of electrical stability than the infarcted animals with normal innervation (Group 4).

Sympathectomy in the treatment of angina and arrhythmias.

Sympathectomy has been used as treatment for several different cardiac conditions. These include classic angina pectoris, Prinzmetal's angina, paroxysmal atrial tachycardia, ventricular tachycardia, and long QT syndrome. To understand the rationale of such treatment, the innervation of the human heart is reviewed with discussion of the cardiac plexus and coronary innervation. Results in published studies are summarized and discussed.

Measuring for improvement: from Toyota to thoracic surgery.

BACKGROUND: Measuring quality has become a high priority in the era of managed care. Nevertheless, it can be counterproductive to use the same methods for measuring improvement in surgical procedures and processes as we use for measurement in basic research. Techniques of statistical process control have been used for many years to measure process improvement in industry and are now being applied to health care. METHODS: Examples of using statistical process control charts to monitor coronary artery bypass grafting mortality, intensive care unit admission time, and length of stay are reviewed. RESULTS: The major advantage of using control chart methodology is that it allows one to determine whether the process being evaluated is in fact stable and to detect when significant or special cause variation occurs. CONCLUSIONS: Summary statistics currently provided to purchasers of care and regulatory agencies do not ensure that the processes being evaluated are stable. We need to look at data over time with statistically validated methods such as control charts to better monitor our processes of care and thereby provide accurate statistics.

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.

Preservation of myocardial high-energy phosphates with vagal stimulation and hypothermic cardioplegia.

We examined three methods of inducing hypothermic cardioplegic arrest and related each to preservation of high-energy phosphates. Levels of adenosine triphosphate (ATP) and creatine phosphate (CP) in baseline rat hearts were compared with levels found after vagal stimulation combined with cardioplegia containing 15 mEq of potassium chloride (KCl) per liter, cardioplegia with 15 mEq of KCl per liter alone, and cardioplegia with 30 mEq of KCl per liter alone. Vagal stimulation produced complete electromechanical arrest in a shorter time than either 15 or 30 mEq of KCl alone (p less than 0.001 for both cardioplegic solutions compared with vagal stimulation), with fewer ventricular beats after ischemia than cardioplegic solution containing 15 or 30 mEq of KCl (p less than 0.001 and less than 0.01, respectively). Levels of ATP and CP, although less than baseline levels (p less than 0.01 and less than 0.001, respectively), were greater with vagal stimulation than with either 15 or 30 mEq of KCl (p less than 0.001 and less than 0.05, respectively, for ATP and p less than 0.001 for both CP levels). Furthermore, when all groups were combined, ATP and CP levels were found to correlate negatively with arrest time (r = -0.851 and -0.788, respectively; both r values significant at p less than 0.01) and with the number of ventricular beats after ischemia (r = -0.927 and -0.851, respectively; both r values significant at p less than 0.01). We conclude that electromechanical work quantified as time to arrest after aortic cross-clamping and as number of ventricular beats after ischemia correlates negatively with ATP and CP levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Technique for repair of left ventricular free wall rupture.

A case of postinfarction left ventricular free wall rupture is reported. The technique used to repair the rupture is described, along with a modification of the technique.

Cardiovascular responses to PEEP and CPAP following repair of complicated congenital heart defects.

Fourteen infants and children ranging in age from 7 months to 8 years were studied in a hemodynamically stable condition following repair of various heart defects. Changes in cardiac index, stroke index, heart rate, systemic vascular resistance, mean arterial pressure, and central venous pressure were evaluated at levels of 0, 5, and 10 cm H2O using positive end-expiratory pressure (PEEP) in 14 patients and continuous positive airway pressure (CPAP) in 3 patients. No significant changes were found in any of the measurements taken at the different levels.

Leiomyosarcoma of the superior vena cava and azygos vein.

A 40-year-old woman presented with facial swelling and pressure sensation of the ears and sinuses. Chest roentgenography revealed a right paratracheal mass, which was confirmed by a venogram, and transjugular biopsy showed low-grade leiomyosarcoma. The superior vena cava was resected and reconstructed using a spiral vein graft. Pathologic evaluation revealed a low-grade leiomyosarcoma arising from both the superior vena cava and the azygos vein with clear margins.

Bradycardia induced by intravascular versus direct stimulation of the vagus nerve.

BACKGROUND: Electrical stimulation of the parasympathetic nervous system results in slowing of the heart. We sought to determine whether cardiac vagal efferent axons can be stimulated adequately to induce bradycardia without disturbing the integrity of the thorax. METHODS: Cardiodepressor effects elicited by direct stimulation of a vagus nerve in anesthetized dogs and pigs were compared with those generated when the same nerve was stimulated indirectly through bipolar electrodes placed in the adjacent superior vena cava. RESULTS: The heart rate of dogs decreased by about 80% when electrical stimuli were delivered to the right thoracic vagus at the level of the thoracic outlet through bipolar electrodes placed either in the adjacent superior vena cava (intravascular method) or directly on the nerve (direct method). Maximal responses were achieved with 10-V, 5-ms, and 20-Hz stimuli. In anesthetized pigs, similar bradycardia occurred when the right cervical vagus or the right cranial thoracic vagus was stimulated either directly or indirectly through the intravascular method. Atrial dysrhythmias occurred when the stimulating electrodes were placed by either method within 1 cm of the right atrium in both animal models. CONCLUSIONS: Controlled bradycardia can be induced during operation without the risk of generating cardiac dysrhythmias using electrical stimuli (10 V, 5 ms, and 10 to 20 Hz) delivered to the right cervical vagus nerve or the right cranial thoracic vagus nerve through adjacent intravascular electrodes.

Heart transplantation.

Modern concepts of cardiac transplantation are reviewed. Selection of potential recipients and donors is discussed with particular attention to those aspects of procurement that involve coordination with other transplant teams. Technical aspects of the operation, postoperative management, immunologic regimens, and late results, including physiologic testing and complications, are also reviewed.

Effect of sleep position on apnea and bradycardia in high-risk infants.

OBJECTIVE: The purpose of this investigation was to investigate, in high-risk infants, the occurrence of abnormalities in documented monitor downloads during the side versus prone position. STUDY DESIGN: Forty infants admitted to the A. I. duPont Hospital for Children with diagnoses associated with sudden infant death syndrome were included in this investigation. During an overnight hospitalization, infants were placed on home apnea monitors, with computer memory to capture alarms for apnea > 20 seconds, age-defined bradycardia, and tachycardia. Infants were studied for 12 hours. Each infant was assigned to 6 hours of prone and side during the 12-hour period, with order of position randomly assigned by random number generation. Differences between the two positions in alarm frequency and significant events, as determined by a blinded interpreting physician were analyzed by Fisher exact test, with p < 0.05. Power analysis necessitated 20 patients in each group, with beta error of 0.2. RESULTS: Eleven episodes of apnea occurred in the prone position, and 16 in the side position (p = NS). The mean numbers of apnea events per tracing in the prone position was 0.27 +/- 0.84 and 0.39 +/- 1.1 in the side position (p = 0.58). The mean number of bradycardia events per tracing in the prone position was 0.44 +/- 1.45 and 0.49 +/- 1.94 in the side position (p = 0.9). CONCLUSION: Clinicians need to be cautious when recommending the side or prone position in this group of high-risk infants. The results in this investigation provide support for the Back to Sleep Campaign recommendations to be applied, not only to healthy term infants, but higher risk infants as well. Studies of the high-risk infant in the supine position are warranted.

Beta receptor derangement in postinfarction left ventricular perianeurysm tissue.

The purpose of this study was to evaluate alterations in adrenergic receptor density in patients with post-infarction left ventricular aneurysms. Resected specimens from 4 patients with left ventricular aneurysm were studied using standard techniques to evaluate beta receptors, alpha receptors, and muscarinic receptors in the border zone, perianeurysm tissue, and infarcted aneurysm tissue. Only the beta receptors demonstrated up-regulation around the aneurysm (p = 0.0003). This indicates that infarction with aneurysm formation can alter adrenergic receptor density, which may affect cellular response and predispose to arrhythmogenesis.

Cardiovascular effects of experimental cerebral missile injury in primates.

Ten rhesus monkeys were subjected to detailed cerebral and cardiac monitoring over a period of 90 minutes following an experimental gunshot wound. Bradycardia, decreased cardiac output, and decreased pulmonary and systemic blood pressures were observed in the presence of normal preloading (right and left atrial pressures) and afterloading (pulmonary and systemic vascular resistances). Defective cardiac output, autoregulation and cerebrovascular resistance were associated with low perfusion pressures, low cerebral blood flow, and low CMRO2.

Depletion of myocardial high energy phosphates by induction of ventricular fibrillation prior to cardioplegic arrest.

The effects of a short period of ventricular fibrillation on myocardial high energy phosphates were assessed in two groups of rats. Group 1 underwent hypothermic crystalloid cardioplegia infusion and aortic cross-clamping. In Group 2, cardioplegia and cross-clamping were preceded by ten seconds of induced ventricular fibrillation. In rat hearts that had undergone ventricular fibrillation, adenosine triphosphate levels averaged only 70% (p less than .0001) and creatine phosphate levels averaged only 60% (p less than .0005) of levels measured following standard cardioplegic arrest without ventricular fibrillation. These findings are of potential importance in both routine cardiac surgical procedures and in organ procurement.

Hypoplastic left heart syndrome: report of an operation utilizing the ductus arteriosis in outflow reconstruction.

An operation utilizing the ductus arteriosus to construct an outflow tract from the right ventricle is described. This operation uses the right ventricle for pulsatile flow to both systemic and pulmonary arteries, provides complete reconstruction of the ascending aorta and arch, and delivers predictable pulmonary blood flow. Although unsuccessful in this case report, which involves a hypoplastic left heart syndrome patient, the technique may provide successful palliation with the use of ductal tissue. This method has not been previously described.