REPAIR OF VENTRICULAR SEPTAL DEFECT FOLLOWING MYOCARDIAL INFARCTION

Principles of closed surgical wound care

A review of the factors before, during and after surgical procedures that may predispose patients to post-operative wound infection

Epidemiological methods in the study of surgical wound infection

Epidemiology can provide the knowledge necessary to allocate resources appropriately, but awareness of the advantages and disadvantages of different study methods is essential

Right ventricular dysfunction in acute ventricular septal defect

Eight patients with acute ventricular septal defect (VSD) receiving early intra-aortic balloon augmentation, cardiac catheterization, and open-heart surgery are described. Because of the large shunts in this group of patients, there was visualization of the right ventricle during left ventriculography which was adequate for qualitative analysis. The following were noted: (1) All patients had severe right ventricular (RV) dysfunction angiographically. (2) RV akinesis noted on angiography was more extensive than the surgical description of RV infarction, although all patients had biventricular infarction at surgery. (3) The RV dysfunction was the major cause of death (two cases) or a contributing factor (three cases). (4) RV papillary muscle rupture was identified in one case.

Aneurysms of the posterior interventricular septum with postinfarction ventricular septal defect. Echocardiographic identification

Using real-time, two-dimensional echocardiographic techniques, we recently studied six consecutive patients with acute myocardial infarction complicated by rupture of the posterior interventricular septum. Each patient experienced an inferior wall myocardial infarction, with a prior anteroseptal infarction in one. In each case, the clinical course was punctuated by the onset of heart failure and a low output state prior to, or coincident with, the appearance of a pansystolic murmur. During two-dimensional echocardiographic study, all six were found to have a discrete aneurysm of the posterior interventricular septum. Septal dyskinesis produced bulging of the interventricular septum far into the right ventricular cavity during systole. Our findings suggest that (1) septal dyskinesis and aneurysm formation may be a valuable sign in diagnosing ventricular septal performation; (2) the reported incidence of postinfarction septal aneurysm at surgery or autopsy may significantly underestimate its true frequency; and (3) septal dyskinesis must by considered as a contributing factor to the compromised hemodynamic status of patients with postinfarction ventricular septal rupture.

Balloon-induced right ventricular outflow obstruction: a new approach to control of acute interventricular shunting after myocardial infarction in canines and swine

Current management of ventricular septal defect (VSD) after myocardial infarction (MI) is aimed at improving left ventricular (LV) performance by afterload reduction as a means of hemodynamic stabilization or shunt control. The current investigation was undertaken to determine whether primary manipulation of right venticular (RV) performance by afterload enhancement was an effective means of reducing MI-VSD shunting. In five open-chest dogs an external LV-RV shunt was created with pulmonary-systemic flow ratios (Qp/Qs) averaging 2.26:1. Inflation of a balloon-tipped catheter in the main pulmonary artery (PA) reduced average QP/Qs to 1.28:1 and shunt flow from 783 to 343 ml/min. However, this increase in RV afterload caused further significant increases in RV systolic and end-diastolic pressure and suggested that deterioration of RV function might be limiting the usefulness of this technique. To investigate whether inotropic support for the RV would overcome this limitation, a similar shunt was created in 11 open-chest swine. We then investigated the effects of dopamine, infused at 24, 60, and 120 mug/min, on QP/QS and other hemodynamic variables both with and without PA balloon inflation. Optimal shunt control was obtained when effects of dopamine were added to those of PA balloon inflation. Shunt flow that had been 1,633 ml/min was reduced to 892 ml/min with the PA balloon and reduced further to 757 ml/min with dopamine, which also lowered RV and LV end-diastolic pressure and reduced total systemic vascular resistance. In four other swine with left anterior descending ligations, PA balloon inflation and dopamine infusion again favorably affected hemodynamics. Epicardial mapping in these swine showed an increase in S-T segment displacement, suggesting that the cumulative effect of these interventions allowed hemodynamic improvement at the expense of enhanced ischemic injury. These data indicate that acute RV outflow obstruction with a balloon catheter is an effective means of temporarily reducing acute ventricular shunting and that dopamine may be a useful pharmacological agent to use with RV afterload manipulation to stabilize a patient prior to transfer to a medical center for more definitive therapy.

Surgical considerations in the treatment of acute acquired ventricular septal defect

In the light of our experience and that of others (Oldham et al., 1969; Iben, Pupello, Stinson, and Shumway, 1969), early surgical closure of acquired ventricular septal defect is advocated. Two successful cases are presented, one after myocardial infarction and one after penetrating trauma to the heart. Description of the present method of repair is presented. Two prosthetic patches are interposed in the closure of the defect. The advantages of this technique are (a) the key sutures are placed through healthy tissue and are anchored by the two patches, and (b) an additional suture line along the free edge of the right ventricular patch ensures a complete closure.

Ventricular septal defect and ventricular aneurysm secondary to acute myocardial infarction. Report of four cases with successful surgical treatment

Four cases of ventricular septal defect and ventricular aneurysm after myocardial infarction are reported. The clinical findings and surgical results in these four cases and in eight previously reported patients with this combination of complications are summarized. Resection of the ventricular aneurysm and closure of the ventricular septal defect appear indicated, both on theoretical grounds and in view of the excellent results observed in six patients who underwent combined repair. In one of our patients, closure of the ventricular septal defect and resection of the ventricular aneurysm were possible with only a single suture line, as these defects were anatomically contiguous.

Peripheral vascular volumes and whole body hematocrit during human heart lung bypass

Indicator-dilution curves were obtained across the peripheral vascular bed in 15 patients soon after the beginning of heart lung bypass, and in eight of these persons they were repeated just prior to the conclusion of bypass. A bolus containing labelled red cells and albumin was injected into the arterial inflow line just proximal to the aorta. Serial blood samples were obtained at intervals of 1 second from the venous return line, just distal to the right atrium, and the radioactivity was measured. The interposed volume of blood in the pump oxygenator delayed recirculation, allowing extrapolation of the exponential downslope and calculation of flow rates and indicator distribution volumes by the Hamilton-Stewart equations.

The distribution volume of albumin (average, 56.3 ml/kg) was always greater than that of red cells (average, 44.8 ml/kg). The average ratio of whole body hematocrit to perfusate hematocrit was 0.873. The absence of significant differences between data obtained at the beginning and just prior to the end of bypass suggests that there were no alterations in venous tone or the volume relationships of large vessels to the microcirculation.

Rupture of the ventricular septum from myocardial infarction. Haemodynamic response to surgical treatment

A patient aged 59 had a coronary thrombosis complicated by a ruptured ventricular septum. This was successfully repaired surgically about three months after the infarct, and some indications and problems connected with this procedure are discussed.

Postinfarction Ventricular Septal Defect

A series of four patients who died following rupture of the ventricular septum due to myocardial infarction has been reported. One of these died of hemorrhage due to a defective clotting mechanism 8 hours after successful surgical repair.

The 13 cases of surgical repair of postinfarction ventricular septal defect reported by other authors are reviewed.

The time interval is important and preferably 3 to 6 months should elapse following myocardial infarction before surgery is undertaken.

Surgery should be considered in every patient diagnosed as having an acute septal rupture following myocardial infarction who fails to respond to vigorous medical treatment.