O-024 UHC Data Indicates Higher Mortality Rate in Aneurysms Embolized with Bare Platinum Coils Compared with Polymer Enhanced Coils
Authors: Alexander M , Nuno M , Chowdhary A , Choulakian A , Schievink W 
Published: July 2011

Introduction

Recently, ICD-9 procedure coding for hospitals has changed to reflect aneurysm embolization with either bare metal coils or polymer-enhanced coils, and 2010 was the first year that an entire calendar year of data are available from the University-Health System Consortium (UHC) Clinical Database that reflects this change. This study evaluated recent trends in preferences of coil types for treating patients diagnosed with ruptured or unruptured aneurysms. Potential differences in the average number of ICU days, percent complications and early mortality are compared according to coil type, aneurysm rupture status and hospital aneurysm embolization volume (high- vs low-volume).

Methods

Using data from the UHC Clinical Database from January 2010 to December 2010, we captured ruptured (ICD-9 code: 430) and unruptured (ICD-9 code: 437.3) aneurysm cases undergoing a coiling procedure (ICD-9 code: 39.75-Bare-Coils, 39.76-Polymer-Coils). Hospitals were stratified into high-volume if they embolized 50 or more cerebral aneurysms for the year; similarly, hospitals were considered low-volume if they embolized <50 aneurysms. Univariate analysis evaluated differences in the average number of ICU days, percent complications and early mortality while adjusting for coil type, aneurysm status and hospital type.

Results

The study queried a total of 3496 aneurysms embolized in 94 UHC member hospitals with the new coding designation. Interestingly, the top 16 hospitals in the database treated over half of all the aneurysms in the database (1801 aneurysms), and the remaining 1695 aneurysms were treated by the other 78 hospitals. Univariate analysis showed that high-volume hospitals were more likely to treat ruptured aneurysms with polymer-enhanced coils than low-volume: High volume- Bare: 57.1%, Polymer: 42.9% and low volume- Bare: 83.8%, Polymer: 16.2% (p<0.001). The overall clinical complications reported for polymer and bare coils showed no difference in either the ruptured or non-ruptured aneurysm groups. However, the number of ICU days (p=0.01), percentage of early deaths (within 2 days of treatment) (p=0.02), and the mortality index (p=0.006) were all statistically worse in the bare coil group compared to the polymer enhanced group when all 3496 aneurysms are analyzed.

Conclusions

UHC data from 2010 demonstrates that patients who had use of bare coils had a longer ICU stay, a higher early death rate, and a higher mortality index than those patients treated with polymer-enhanced coils. Although these treatment groups were not randomized, this data shows, in the real-world treatment environment currently, that patients treated with polymer-enhanced coils have better outcomes than those treated with bare coils in both the ruptured and non-ruptured groups.

Abstract O-024 Table 1All aneurysmsBare coilsPolymer coilsp ValueAverage ICU days8.436.920.01Complication rate18.8317.910.12% of Early deaths1.430.100.002Mortality index0.540.380.006