Literature
Clinical Pearls & Morning Reports
Published March 13, 2024
How is ventricular septal rupture managed before definitive surgical repair?
Ventricular septal rupture can be accompanied by a harsh systolic murmur at the middle or lower left sternal border, left-to-right shunting detected on echocardiography or contrast ventriculography, and a step-up in oxygen saturation from the right atrium to the right ventricle. Read the NEJM Case Records of the Massachusetts General Hospital here.
Clinical Pearls
Q: In what percentage of cases is myocardial infarction with cardiogenic shock a result of myocardial rupture?
A: Pump failure due to severe left ventricular systolic dysfunction is the leading cause of acute myocardial infarction complicated by cardiogenic shock, accounting for nearly 80% of cases. Mechanical complications of myocardial infarction — such as rupture of the ventricular septum, papillary muscle, or left ventricular free wall — account for approximately 12% of cases. The incidence of mechanical complications has decreased considerably over the past four decades, in temporal association with the increasing use of early reperfusion therapy, particularly primary PCI.
Q: What are the risk factors for myocardial rupture after myocardial infarction?
A: Risk factors for the various types of myocardial rupture include older age, female sex, hypertension, a first infarction, the absence of a collateral blood supply, and the use of medications that may interfere with wound healing, such as glucocorticoids or nonsteroidal antiinflammatory drugs. The time course of myocardial rupture is bimodal, with one peak occurring within the first 24 hours and the other peak occurring 3 to 5 days after myocardial infarction.
Morning Report Questions
Q: How is ventricular septal rupture managed before definitive surgical repair?
A: Preoperative stabilization before the definitive surgical treatment of ventricular septal rupture typically involves medical therapy or temporary mechanical circulatory support. Hemodynamic goals for such therapies include normalizing the blood pressure and forward cardiac output, maintaining the pulmonary artery pressure and central venous pressure within the normal ranges, and reducing the flow through the pulmonary vasculature. In patients with acute ventricular septal rupture with left-to-right shunting, the flow through the pulmonary vasculature can reach 2 to 3 times the normal rate (e.g., 8 to 10 liters per minute), with the ratio of pulmonary to systemic flow typically ranging from 3 to 4. However, patients with ventricular septal rupture have a wide range of hemodynamic profiles, depending on the size of the ventricular septal rupture and the degree to which ventricular contractility is compromised by the infarction. This variability necessitates a customized approach to therapeutic decision making that can be guided, in part, by hemodynamic data obtained on pulmonary artery catheterization when feasible.
Q: What sequence of therapies might reasonably be used to provide temporary mechanical circulatory support in cases of ventricular septal rupture?
A: Because medical therapies are typically insufficient in patients with acute myocardial infarction complicated by cardiogenic shock and ventricular septal rupture, temporary mechanical circulatory support is often considered. Case reports and small case series of mechanical circulatory support include the use of an intraaortic balloon pump, a percutaneous transaortic ventricular assist device, a transeptal bypass system from the left atrium to the femoral artery, or extracorporeal membrane oxygenation (ECMO). Owing to a lack of data, there is no agreed-upon approach to the treatment of ventricular septal rupture as a complication of myocardial infarction. The choice therefore largely depends on device availability, local expertise, the severity of hemodynamic compromise, and whether supplemental oxygenation of the blood is needed. The following sequence of therapies may be a reasonable approach: initial medical therapy, followed by the use of an intraaortic balloon pump, and then followed by the use of either a ventricular assist device or ECMO.