Better prognosis in surgical aortic valve replacement patients with lower red cell distribution width: A MIMIC-IV database study

BACKGROUND

Surgical aortic valve replacement (SAVR) currently stands as a primary surgical intervention for addressing aortic valve disease in patients. This retrospective study focused on the role of the red blood cell distribution width (RDW) in predicting adverse outcomes among SAVR patients.

METHODS

The subjects for this study were exclusively derived from the Medical Information Mart for Intensive Care database (MIMIC IV 2.0). Kaplan‒Meier (K-M) curves and Cox proportional hazards regression models were employed to assess the correlation between RDW, one-year mortality, and postoperative atrial fibrillation (POAF). The smooth-fitting curves were used to observe the relative risk (RR) of RDW in one-year mortality and POAF. Furthermore, time-dependent receiver operating characteristic (ROC) curves, the continuous-net reclassification index (NRI), and integrated discrimination improvement (IDI) were employed for comprehensive assessment of the prognostic value of RDW.

RESULTS

Analysis of RDW revealed a distinctive inverted U-shaped relationship with one-year mortality, while its association with POAF appeared nearly linear. Cox multiple regression models showed that RDW > 14.35%, along with preoperative potassium concentration and perioperative red blood cell transfusion, were significantly linked to one-year mortality (K-M curves, log-rank P < 0.01). Additionally, RDW was associated with both POAF and prolonged hospital stays (P < 0.05). There was no significant difference in length of stay in ICU. Notably, the inclusion of RDW in the predictive models substantially enhanced its performance. This was evidenced by the time-dependent ROC curve (AUC = 0.829), NRI (P< 0.05), IDI (P< 0.05), and K-M curves (log-rank P< 0.01).

CONCLUSIONS

RDW serves as a robust prognostic indicator for SAVR patients, offering a novel means of anticipating adverse postoperative events.

Late incidence and recurrence of new-onset atrial fibrillation after isolated surgical aortic valve replacement

OBJECTIVES

Atrial fibrillation (AF) is a common complication after cardiac surgery. More knowledge is needed about long-term AF recurrence and adverse outcomes related to new-onset AF (NOAF) during the index hospitalization.

METHODS

A total of 1073 patients underwent isolated surgical aortic valve replacement at the 4 participating hospitals (2002-2014). After the exclusion of patients with a history of any preoperative AF, the final study population included 529 patients in the bioprosthetic and 253 patients in the mechanical valve prosthesis cohort. Median follow-up time was 5.4 (interquartile range, 3.4-8.2) years in the combined cohort.

RESULTS

Altogether 333 (42.6%) patients had in-hospital NOAF and 250 (32.0%) AF after hospital discharge. In the mechanical cohort, 64 (25.3%) experienced in-hospital NOAF and 74 (29.2%) AF after hospital discharge, whereas in the bioprosthetic cohort, 269 (50.9%) patients had in-hospital NOAF and 176 (33.3%) AF after hospital discharge. Patients with NOAF during the index hospital stay had a multifold risk of AF after hospital discharge in the combined cohort (hazard ratio [HR], 3.68; 95% confidence interval [CI], 2.82-4.81; P < .0001) as well as in both cohorts separately (bioprosthetic: HR, 4.35; 95% CI, 3.05-6.22; P < .001; mechanical: HR, 2.54; 95% CI, 1.59-4.03; P < .001). Patients with an in-hospital NOAF also had a significantly higher adjusted risk of death during the follow-up in the mechanical (HR, 2.05; 95% CI, 1.10-3.82; P = .025) and bioprosthetic (HR, 1.63; 95% CI, 1.17-2.28; P = .004) valve prosthesis cohorts.

CONCLUSIONS

NOAF during the index hospitalization is associated with a 2- to 4-fold risk of later AF and 1.6- to 2.0-fold risk of all-cause mortality after mechanical and bioprosthetic surgical aortic valve replacement.

Long-term Thromboembolic Risk in Patients With Postoperative Atrial Fibrillation After Left-Sided Heart Valve Surgery

Importance

New-onset postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery. However, data on the long-term risk of thromboembolism in patients who develop POAF after heart valve surgery are conflicting. In addition, data on stroke prophylaxis in this setting are lacking.

Objective

To assess the long-term risk of thromboembolism in patients developing new-onset POAF after isolated left-sided heart valve surgery relative to patients with nonsurgical, nonvalvular atrial fibrillation (NVAF).

Design, Setting, and Participants

This observational cohort study was conducted from January 1, 2000, through December 31, 2015, using Danish nationwide registries and the Eastern Danish Heart Surgery Database. Patients who developed POAF after isolated left-sided heart valve surgery (bioprosthetic aortic or mitral valve replacement and/or aortic or mitral valve repair) from 2000 through 2015 were included. These patients were matched with patients with nonsurgical NVAF in a 1:3 ratio by age, sex, heart failure, hypertension, diabetes, a history of thromboembolism, ischemic heart disease, and year of diagnosis. Data analyses took place from January to March 2019.

Main Outcomes and Measures

Rates of thromboembolism.

Results

Of the 1587 patients who underwent isolated left-sided heart valve surgery, 741 patients (46.7%) developed POAF during admission. Of the 712 patients with POAF who were eligible for matching, 675 patients were matched with 2025 patients with NVAF and made up the study population. In the matched study population, the median age was 71 (interquartile range, 65-77) years, and 1600 (59.3%) were men. Oral anticoagulation therapy was initiated within 30 days postdischarge in 420 patients with POAF (62.9%) and in 1030 patients with NVAF (51.4%). The crude incidence rates of thromboembolism were 21.9 (95% CI, 17.4-27.6) and 17.7 (95% CI, 15.2-20.6) events per 1000 person-years for patients with POAF and patients with NVAF, respectively. In the adjusted analysis, the long-term risk of thromboembolism was similar in patients with POAF and NVAF (hazard ratio, 1.22 [95% CI, 0.88-1.68]). Oral anticoagulation therapy during follow-up was associated with a lower risk of thromboembolic events in patients with POAF (hazard ratio, 0.45 [95% CI, 0.22-0.90]) as well as patients with NVAF (hazard ratio, 0.63 [95% CI, 0.45-0.87]) compared with no anticoagulation therapy.

Conclusions and Relevance

New-onset POAF after isolated left-sided heart valve surgery was associated with a similar long-term risk of thromboembolism as NVAF. These data warrant studies addressing the role of anticoagulation therapy in POAF after left-sided heart valve surgery.