Introduction: The role of pre-implant and intra-procedural parameters on mortality and hospitalisation for heart failure (HHF) in patients undergoing implantation with cardiac resynchronization therapy pacemaker (CRT-P) or defibrillator (CRT-D) versus CRT upgrade is poorly defined. In the present study we aimed to evaluate mortality predictors and clinical outcomes in patients undergoing CRT-P/D versus CRT upgrade.
Methods: This was a single-centre retrospective study of nine-hundred and thirty-three (933) patients receiving de novo implantation of CRT-P/D or CRT upgrade between 2016-2020: CRT-P (n=264), CRT-D (n=448), and CRT upgrade (n=221). The mean left ventricular ejection fraction was 34.9 ± 12.8 and median follow-up was 29.0 (17-41) months.
Results: We found that recipients of CRT-D were significantly younger (68.0 ± 11.9) than CRT-P (76.2 ± 10.8) and upgrade (71.8 ± 14.0; p<0.001) and had a higher uptake of oral anticoagulants (p=0.001) and aldosterone antagonists (p<0.001). CRT-P recipients were more likely to have baseline atrial fibrillation (AF; p<0.001). Overall mortality was significantly higher in upgrade (14.1%) and CRT-P (12.9%) patients versus those receiving CRT-D (8.7%) (p=0.039). On multivariate analysis, chronic kidney disease (CKD) and anaemia predicted both mortality (OR: 3.5 [2.1-5.9; 95% CI] p<0.001, and OR: 1.8 [1.1-3.2; 95% CI] p=0.024, respectively) and HHF (OR: 3.8 [1.6-9.2; 95% CI] p=0.003, and OR: 2.9 [1.3-6.6, 95% CI] p=0.012, respectively). In addition, the presence of diabetes mellitus predicted HHF (OR: 2.2 [1.0-4.7; 95% CI] p=0.047), while AF was associated with a higher likelihood of mortality as compared to patients in sinus rhythm (13.6% vs. 10.1%; p=0.045). In patients with CRT-D, use of a bipolar lead was associated with a significantly higher rate of mortality (16.7% vs. 10.7%; p=0.024) and HHF (8.0% vs. 4.0%; p=0.011) compared with use of a multipolar lead.
Conclusion: Our results showed that mortality is higher in patients receiving CRT upgrade or CRT-P as compared to CRT-D recipients. In addition, CKD, anaemia, diabetes mellitus, and presence of AF are associated with either higher mortality or HHF or both. The use of bipolar leads in patients with CRT-D was associated with poorer clinical outcomes compared to use of multipolar leads.
