Relationship between hospital volume and major cardiac complications of rotational atherectomy: A nationwide retrospective cohort study in Japan.
BACKGROUND
Previous studies on life-threatening complications of rotational atherectomy (RA) were based on small sample sizes from a limited number of cardiovascular centers. No study has examined the relationship between hospital volume of RA and complications.


METHODS
Using the Diagnosis Procedure Combination database in Japan, we identified inpatients aged ≥20 years who underwent RA. Hospital volume was defined as the annual number of patients undergoing RA at each hospital and eligible patients were categorized into hospital-volume tertile (low-, medium-, and high-volume) groups. The composite outcome consisted of cardiac complications requiring urgent procedures (covered stent implantation, coronary artery bypass grafting, or pericardiocentesis) or death on the day of RA. We examined the association between hospital-volume categories and the composite outcome by using a multivariable logistic regression model fitted with a generalized estimating equation.


RESULTS
A total of 9970 patients (median age, 73 years; male, 69.8%) underwent RA in 309 hospitals. The 309 hospitals were categorized into 215 low-volume (≤15/year), 67 medium-volume (16-30/year), and 27 high-volume hospitals (≥31/year). Overall, the composite outcome occurred in 62 (0.62%) patients (36 covered stent implantation, 11 coronary artery bypass grafting, 9 pericardiocentesis, and 14 death). Patients in the high-volume group had a significantly lower rate of the composite outcome (0.29%) than those in the low-volume (0.72%, p=0.010) or medium-volume group (0.89%, p=0.001). With reference to the low-volume group, risk-adjusted odds ratios (95% confidence intervals) of the medium-volume and high-volume groups for the composite outcome were 1.10 (0.64-1.89) and 0.42 (0.20-0.88), respectively.


CONCLUSIONS
This study showed that higher hospital volume was significantly associated with lower complication rates of RA. Our results also suggested that the major complication rates were low even in low-volume hospitals.
Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan; Department of Cardiology, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan. Electronic address: toisogai-circ@umin.ac.jp.
Toshiaki
T
Isogai
Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
Hideo
H
Yasunaga
Department of Clinical Epidemiology and Health Economics, School of Public Health, The University of Tokyo, Tokyo, Japan.
Hiroki
H
Matsui
Department of Cardiology, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan.
Hiroyuki
H
Tanaka
Department of Health Policy and Informatics, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
Kiyohide
K
Fushimi
D000368:Aged; D000369:Aged, 80 and over; D017225:Atherectomy, Coronary / Q000009:adverse effects* / Q000401:mortality; D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D016208:Databases, Factual; D005260:Female; D061847:Hospitals, High-Volume; D061846:Hospitals, Low-Volume; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention / Q000706:statistics & numerical data; D020519:Pericardiocentesis / Q000706:statistics & numerical data; D011183:Postoperative Complications; D012189:Retrospective Studies; D015607:Stents / Q000706:statistics & numerical data
Coronary artery bypass grafting; Covered stent; Hospital volume; Percutaneous coronary intervention; Rotational atherectomy