Postinfarction ventricular septal defect: delayed closure with prolonged mechanical circulatory support

Left-to-right shunt reduction with intra-aortic balloon pump in postmyocardial infarction ventricular septal defect

This case aims to describe the hemodynamic effects of intra-aortic balloon pump (IABP) in patients with ventricular septal defect (VSD) complicating myocardial infarction (MI). A 79-year-old man with no previous cardiovascular history presented to the emergency department with subacute inferior myocardial infarction associated with mild signs of systemic hypoperfusion. A transthoracic echocardiography revealed a large akinesia of the left ventricular inferior wall with preserved global left ventricular ejection fraction, as well as a large VSD in the midinferior portion of the interventricular septum. Coronary angiography showed an occlusion of the mid portion of a dominant circumflex coronary artery. The invasive hemodynamic evaluation showed a sizable left-to-right shunt (Q(p)/Q(s) = 3.1). Activation of the IABP led to an immediate reduction of the shunt (Q(p)/Q(s) = 2.4 = 22% reduction), an increase in systemic cardiac output (from 2.1 L/min to 2.4 L/min = +12%) and a decrease in the systemic vascular resistances (from 2240 to 1920 dyne-sec/cm(5) = 15% reduction). In patients with post-MI VSD, placement of IABP leads to an immediate reduction in left-to-right shunt and as a consequence to an increase in systemic cardiac output, which may allow hemodynamic stabilization of the patient prior to surgical VSD closure.

Surgical Repair of Mechanical Complications of Myocardial Infarction

Mechanical complications of acute myocardial infarction are estimated to account for 25,000 fatalities yearly in the United States. The diagnosis necessitates a high degree of clinical suspicion. Once recognized, prompt surgical intervention is necessary because if left untreated the condition frequently causes a fatal outcome. The main determinants of survival are the preoperative hemodynamic status of the patient, the presence of multisystem failure at presentation, and concomitant revascularization during repair of the defect. Because ischemic heart disease remains the leading cause of death in such patients following repair, coronary artery bypass should be considered and, whenever possible, performed in conjunction with repair of the postinfarct mechanical complication.

Short- and long-term hemodynamic effects of intra-aortic balloon support in ventricular septal defect complicating acute myocardial infarction

In patients with an infarct-related ventricular septal defect, an intra-aortic balloon pump provides immediate and long-term hemodynamic improvement, resulting in an enhanced effective cardiac output and a reduced left-to-right-shunt and shunt flow ration. In patients who can be stabilized or remain stable, there is no habituation to the effects of the intra-aortic balloon pump; thus, later surgical closure of the ventricular septal defect might be possible in some patients.

Mechanical Support After Cardiac Surgery

Mechanical circulatory support for low cardiac output after cariac surgery was first attempted in 1962. Since then, many ventricular assist devices have been developed and employed. The following is a discussion of the history, demographics, inications, and devices used for mechanical circulatory suport in this setting. lntra-aortic balloon pulsation, pulsatile verus non-pulsatile flow, volume bypass, roller and centrifugal pumps, extracorporeal membrane oxygenation, and imlantable devices are reviewed. Early postoperative care, reovery and weaning from mechanical circulatory support, and the special issues that relate to biventricular failure and control of right-sided ventricular function, as well as anticoagulation, and sepsis are addressed.

Postinfarction ventricular septal defect

Despite improved screening and diagnostic capabilities for the presence of coronary artery disease (CAD), with the promise of improved outcomes from earlier therapeutic interventions, postinfarction ventricular septal perforation (VSD) continues to be a very difficult therapeutic challenge. In our experience with VSD, the incidence of this complication per year has decreased, almost certainly related to earlier and more effective medical therapy in patients with CAD. By contrast, the outcomes of surgical repair have not improved, even with an aggressive strategy about bypassing involved coronary arteries. Furthermore, the earliest possible surgical approach and the incorporation of a number of technical advances, especially those relating to myocardial preservation, have not had an apparent effect. Because the number of patients who underwent operation is small, it is not possible from our single-institutional experience to define statistical significance to our continuing observations of this condition, suggesting that the clinical spectrum of postinfarction VSD is still evolving. Important changes appear to be associated with an increase in the number of female patients observed (60%), in contrast to their lesser frequency of uncomplicated coronary bypass (18%) and a change in the anatomic substrate, with posterior infarctions and rupture now accounting for 73% of cases at Cedars-Sinai. For the present, earliest possible surgical intervention to minimize the severity of multi-organ failure and use all of the advanced therapeutic modalities of cardiac support and surgical therapy that are available continues to be indicated. For the long term, continuing advances in the earlier diagnosis and more aggressive management of CAD, especially in females, may hold the best promise for a continued decrease in the occurrence of this very difficult-to-treat postinfarction complication.

Urgent surgical repair of postinfarction ventricular septal rupture: early and late outcome

AIM

This retrospective analysis focuses on predictive factors of operative mortality and long-term survival after surgical repair of postinfarction ventricular septal rupture (VSR).

METHODS

Sixty-seven patients (43 males, 24 females) with VSR underwent surgical repair between December 1977 and December 1995. The site of the rupture was anterior in 44 patients and posterior in 23. The mean interval between myocardial infarction (MI) and VSR was 3.6+/-4.1 days. Clinical condition on admission was critical in 63 patients (49 in cardiogenic shock). An intra-aortic balloon pump was inserted preoperatively in 54 patients.

RESULTS

Operative mortality was 25% (17 patients). The main cause of death was cardiac failure. Factors influencing early deaths in univariate analysis were preoperative hemodynamic status (cardiogenic shock present in 30%; absent in 8%; p = 0.001), the location of the MI (anterior in 11.6%, posterior in 45.4%), the interval between infarction and surgery (<1 week was 33%, >1 week was 6.2%), and the response to initial active therapy. All patients were available for follow-up. The actuarial survival rates at 1 and 5 years are 74.6%+/-5.3% and 66.2%+/-6.2%, respectively. There were 12 late deaths and 40% were cardiac related. Two patients presented residual VSD (one reoperation). The left ventricular ejection fraction (LVEF) was mildly impaired in 9 patients. Three patients had moderate mitral insufficiency and two had moderate tricuspid insufficiency.

CONCLUSION

Repair of the postinfarction VSR remains a challenge. Improvement should be rendered possible by optimizing techniques. Postoperative morbidity is high, and these patients require intensive hospital resources. The late results have been satisfactory.

Surgical treatment of postinfarction ventricular septal defect with aortic stenosis

A 69-year-old man with an acute postinfarction ventricular septal defect was also found to have aortic stenosis. Successful management required closure of the postinfarction ventricular septal defect and replacement of the stenotic aortic valve. The contribution of aortic stenosis to the cause of the infarction and the postinfarction ventricular septal defect, as well as the implications for surgical management, are discussed.

Surgical management of postinfarction ventricular septal rupture

Recognition and treatment of patients with ventricular septal rupture following infarction have improved over the past 25 years to the extent that survival with good long-term palliation is achieved in the majority of patients treated surgically for this catastrophic complication of acute myocardial infarction. The small minority of patients who, by the process of selection, are seen for surgical correction of septal rupture several weeks after infarction routinely have repair of the septal defect with an operative risk of less than 10%. With increasingly early diagnosis of septal rupture, the majority of patients are seen for consideration of surgical repair often within hours after septal rupture. Most such patients seen early after septal rupture exhibit cardiogenic shock. Refinement of operative techniques both for suture repair of freshly infarcted myocardium and for repair of defects in different anatomical locations has markedly improved survival in these critically ill patients. Deferral of operation for the patient in cardiogenic shock after septal rupture represents a failed therapeutic strategy. Conversely, emergency operation for the patient with septal rupture and cardiogenic shock has markedly improved survival in this high-risk group. Prolonged intraaortic balloon pump support and deferred operation should be reserved for the uncommon patient who, because of delayed diagnosis or referral, is seen in an advanced stage of multisystem failure in which the risks of early operative intervention involve the function of organs other than the heart.