Surgery (Austin & Northern Health) - Research Publications
Permanent URI for this collection
Search Results
1 - 2 of 2
-
ItemRelationship between QT interval prolongation and structural abnormalities in cirrhotic cardiomyopathy: A change in the current paradigm(WILEY, 2021-06)It is postulated that cardiac structural abnormalities observed in cirrhotic cardiomyopathy (CCM) contribute to the electrophysiologic abnormality of QT interval (QTc) prolongation. We sought to evaluate whether QTc prolongation is associated with intrinsic abnormalities in cardiac structure and function that characterize CCM. Consecutive patients undergoing liver transplant work-up between 2010 and 2018 were included. Measures of cardiac function on stress testing including cardiac reserve and chronotropic incompetence were collected prospectively and a corrected QTc ≥ 440 ms was considered prolonged. Overall, 439 patients were included and 65.1% had a prolonged QTc. There were no differences in markers of left ventricular and atrial remodeling, or resting systolic and diastolic function across QTc groups. The proportion of patients that met the criteria for a low cardiac reserve (39.2 vs 36.6%, p = .66) or chronotropic incompetence (18.1 vs 21.3%, p = .52) was not different in those with a QTc ≥ 440 vs <440 ms. Further, there was no association between QTc prolongation and CCM by either the 2005 World College of Gastroenterology or modified 2020 Cirrhotic Cardiomyopathy Consortium criteria. QT interval prolongation was not associated with structural or functional cardiac abnormalities that characterize CCM. These findings suggest that CCM and QT interval prolongation in cirrhosis may be two separate entities with distinct pathophysiological origins.
-
ItemEffect of QT interval prolongation on cardiac arrest following liver transplantation and derivation of a risk index(WILEY, 2021-02)Liver transplantation (LT) has a 4-fold higher risk of periprocedural cardiac arrest and ventricular arrhythmias (CA/VAs) compared with other noncardiac surgeries. Prolongation of the corrected QT interval (QTc) is common in patients with liver cirrhosis. Whether it is associated with an increased risk of CA/VAs following LT is unclear. Rates of 30-day CA/VAs post-LT were assessed in consecutive adults undergoing LT between 2010 and 2017. Pretransplant QTc was measured by a cardiologist blinded to clinical outcomes. Among 408 patients included, CA/VAs occurred in 26 patients (6.4%). QTc was significantly longer in CA/VA patients (475 ± 34 vs 450 ± 34 ms, P < .001). Optimal QTc cut-off for prediction of CA/VAs was ≥480 ms. After adjustment, QTc ≥480 ms remained the strongest predictor for the occurrence of CA/VAs (odds ratio [OR] 5.2, 95% confidence interval [CI] 2.2-12.6). A point-based cardiac arrest risk index (CARI) was derived with the bootstrap method for yielding optimism-corrected coefficients (2 points: QTc ≥480, 1 point: Model for End-Stage Liver Disease [MELD] ≥30, 1 point: age ≥65, and 1 point: male). CARI score ≥3 demonstrated moderate discrimination (c-statistic 0.79, optimism-corrected c-statistic 0.77) with appropriate calibration. QTc ≥480 ms was associated with a 5-fold increase in the risk of CA/VAs. The CARI score may identify patients at higher risk of these events. Whether heightened perioperative cardiac surveillance, avoidance of QT prolonging medications, or beta blockers could mitigate the risk of CA/VAs in this population merits further study.