L-Carnitine supplementation for the prevention of postoperative atrial fibrillation in aortic valve surgery.

OBJECTIVES: L-Carnitine, a quaternary amine, improves fatty acid metabolism in the heart and has anti-inflammatory effects. Several studies have reported the efficacy of L-carnitine for the prophylaxis of arrhythmia. We assessed the clinical effectiveness of L-carnitine in preventing postoperative atrial fibrillation (POAF) in aortic valve surgery. METHODS: Thirty patients who underwent aortic valve surgery were included. Fifteen patients had no prophylaxis other than conventional measures (control), while 15 patients received oral L-carnitine for 9 days (daily dose of 3 g). The incidence of POAF during 1 week after surgery was compared between the two groups. The multivariable logistic regression analysis for POAF was performed using the pre- and intraoperative parameters. RESULTS: Preoperative characteristics and operative data were comparable between the groups. The POAF rate was significantly lower in the L-carnitine group than in the control (20% and 60%, respectively; P = 0.025). L-Carnitine use was an independently negative predictor for POAF (odds ratio 0.067; 95% confidence interval 0.006-0.768). CONCLUSIONS: L-Carnitine administration may have potential for the prevention of POAF in aortic valve surgery.

Perioperative changes of the slope in the preload recruitable stroke work relationship by a single-beat technique after mitral valve surgery in functional mitral regurgitation with non-ischemic dilated cardiomyopathy.

OBJECTIVES: The slope in the preload recruitable stroke work relationship is a highly linear, load-insensitive contractile parameter. However, the perioperative change of the slope has not been reported before. We examined the perioperative slope from a steady-state single beat in patients with functional mitral regurgitation and assessed the correlation with brain natriuretic peptide (BNP) levels. METHODS: The study included 16 patients with non-ischemic dilated cardiomyopathy and refractory heart failure: 10 patients underwent mitral valve plasty and left ventricular plasty (MVP + LVP group) and 6 patients who underwent mitral valve replacement and papillary muscle tugging approximation (MVR + PMTA group). The left ventricular ejection fraction was assessed by the modified Simpson method; the slope was assessed by the single-beat technique using transthoracic echocardiography. BNP levels were measured by chemiluminescent immunoassay. RESULTS: The left ventricular ejection fraction and slope did not significantly change from pre- to early post-surgery in the MVP + LVP group. Both the left ventricular ejection fraction and slope significantly increased 6 months after surgery in the MVR + PMTA group. Postoperative BNP level was low in the MVR + PMTA group. While the postoperative left ventricular ejection fraction did not correlate with BNP levels, the postoperative slope significantly correlated with BNP level after surgery in the MVP + LVP group and in the total functional mitral regurgitation group. CONCLUSIONS: The change of slope was dependent on surgical procedures. In functional mitral regurgitation, the slope may be a more sensitive parameter in reflecting the left ventricular contractile function than the left ventricular ejection fraction.

Risk factors for residual mitral regurgitation after aortic valve replacement in patients with severe aortic valve stenosis and moderate mitral regurgitation.

OBJECTIVES: While it was reported that patients with residual moderate mitral regurgitation (MR) after surgical aortic valve replacement (SAVR) had a poorer prognosis than those without it, the risk factors for residual MR have not been fully elucidated. The aim of the study was to evaluate risk factors for residual MR after SAVR. METHODS: Of the 222 patients who underwent isolated SAVR from 2001 to 2018, 33 (11 men; age: 74 ± 7 years) had functional moderate MR before surgery. The risk factors for residual MR were evaluated by comparing patients with residual moderate MR (n = 11, 33%) with those who exhibited improved post-surgery MR (n = 22, 67%). RESULTS: The left atrial diameter was significantly larger in the residual MR group (51 ± 7 mm) than in the improved MR group (46 ± 5 mm; P = 0.049). The mean pressure gradient at the aortic valve was significantly smaller in the residual MR group (52 ± 18 mmHg) than in the improved MR group (69 ± 22 mmHg; P = 0.043). A ratio of left atrial diameter (mm) and mean aortic valve pressure gradient (mmHg) greater than 0.9 predicted residual MR with a sensitivity of 70% and a specificity of 74% (area under the ROC curve: 0.779; P = 0.015). CONCLUSIONS: In patients with severe aortic valve stenosis and moderate MR, a high ratio of preoperative left atrial diameter and mean aortic valve pressure gradient would be a parameter predicting residual moderate MR post-SAVR.