Hyperlactatemia as a Risk Stratification for Postinfarction Ventricular Septal Rupture

Abstract

Background: Surgical repair for postinfarction ventricular septal rupture (VSR) is a challenging operation, especially in the acute phase with unstable hemodynamics. We retrospectively examined the value of measuring lactate, which can be a quantitative indicator of end-organ ischemia caused by multiple factors including ineffective cardiac output, for risk stratification in patients undergoing surgical repair. Methods: From April 2008 to December 2018, 33 consecutive patients were admitted to our hospital with a diagnosis of VSR and underwent VSR repair surgery within 24 hours of admission. We categorized patients into 3 groups based on the distribution of preoperative blood lactate level: <5 mmol/L (n = 16), 5 to 10 mmol/L (n = 11), and >10 mmol/L (n = 6). Results: There was no intraoperative death, but the prognosis for patients with lactate >10 mmol/L was extremely poor, with a median postoperative survival time of only 23 days [25th percentile 6, 75th percentile 30]. Five of 6 patients (83%) died within 30 days after surgery. The risk-adjusted hazard ratio (95% confidence interval) for mortality per 1 SD (0.41-unit) increase in log-transformed preoperative lactate level (equivalent to a 4.10-fold increase) was 2.85 (1.57 to 5.19). Patients with lactate 5 to 10 mmol/L had 3.95-fold and those with lactate >10 mmol/L had 6.03-fold higher risk of mortality than those with lactate <5 mmol/L. Conclusion: Elevation of preoperative serum lactate is significantly associated with mortality in patients who underwent VSR repair. The findings of this study highlight the value of measuring lactate level for risk stratification.