Statewide Highlights | Coronary Artery Bypass Graft (CABG) Surgery 2000

Pennsylvania's Guide to Coronary Artery Bypass Graft (CABG) Surgery 2000 - Statewide Highlights

Measures such as mortality, readmissions, and length of stay are important components in evaluating quality of care for CABG surgery, and reporting these measures for hospitals and surgeons provides specific information that can be used in making health care decisions.

At the same time, a more general evaluation can shed light on how these and other measures play a role in CABG surgery. The following points summarize additional analyses conducted for this report. These findings represent preliminary steps in evaluating these types of relationships and require further study and evaluation.

Statewide Figures for CABG Surgery
In-Hospital mortality rate	2.4%
30-Day mortality rate	2.7%
7-Day readmission rate	6.2%
30-Day readmission rate	14.5%
Average post-sugical length of stay	5.8 days
Average hospital charge	$59,939

Open Heart Surgery Volume for Hospitals and Surgeons

Studies have indicated that procedure volume is associated with better outcomes. For this evaluation, the volume of procedures refers to total open heart procedures, including CABG surgery.
The number of open-heart procedures performed in Pennsylvania hospitals has remained relatively constant since 1995. In 2000, 27,446 procedures were performed - only a slight increase over the 27,264 procedures performed in 1995. The average hospital volume decreased from 634 procedures in 1995 to 499 procedures in 2000. The average surgeon volume was the same (149 procedures) in both 1995 and 2000.
For this analysis, surgeon volume was a significant determinant of patient survival, readmission rates, and post-surgical length of stay - after accounting for patient risk. Specific findings are discussed below.
Surgeon volume and mortality. Surgeon volume was a more important predictor than hospital volume of whether a patient died in the hospital or within 30 days of the CABG surgery. This confirms results from PHC4's 1994/1995 CABG report in which surgeon volume was found to be an important determinant of in-hospital mortality, when, in general, higher volume was associated with increased survival.
In this 2000 report, the likelihood of in-hospital mortality increased as the number of procedures performed by a surgeon increased, up to 115 procedures per year. As the number of procedures increased to more than 115 per year, the likelihood of in-hospital mortality decreased. For example, patients treated by surgeons who performed 200 procedures per year were 9% less likely to die in the hospital than patients treated by surgeons who performed 115 procedures per year. A similar pattern was seen with regard to 30-day post-surgical mortality. For example, patients treated by surgeons who performed 200 procedures per year were 12% less likely to die within 30 days than patients treated by surgeons who performed 92 procedures per year.
Surgeon volume and readmissions. Surgeon volume was a more important predictor than hospital volume of whether a patient was readmitted within 30 days of the CABG surgery. (Surgeon volume was not a significant predictor of readmission within 7 days). The likelihood of a patient being readmitted within 30 days of the CABG surgery decreased as the number of procedures performed by a surgeon increased, up to 190 procedures per year. For example, patients treated by surgeons who performed 190 procedures per year were 6% less likely to be readmitted within 30 days than patients treated by surgeons who performed 100 procedures per year. However, as the number of procedures increased over 190 per year, the likelihood of readmission increased.
Surgeon volume and length of stay. In general, patients treated by surgeons with higher volume had shorter post-surgical lengths of stay.

Surgeon Experience

On average, the surgeons in this report had 13 years of experience performing open heart surgery.
After accounting for patient risk, the number of years of experience surgeons had in performing open heart surgery was an important predictor in patient survival (both in-hospital and within 30-days of the surgery), the likelihood of readmission (for both 7-day and 30-day readmissions), and post-operative length of stay. Details of these findings are discussed below.
Surgeon experience and mortality. Patients treated by surgeons with 8 years of experience were less likely to die in the hospital than patients treated by surgeons with less experience. Mortality increased, however, as surgeon experience increased beyond 8 years (up to approximately 23 years of experience). In-hospital mortality began to decrease for patients treated by surgeons with more than 23 years of experience. A similar pattern was seen with regard to 30-day mortality rates.
Surgeon experience and readmissions. The likelihood of a patient being readmitted increased for less experienced surgeons (up to, and including, about five years of experience) and then decreased among more experienced surgeons (those with roughly 6 to 21 years of experience). For example, patients who were treated by surgeons with 21 years of experience were 10% less likely to be readmitted within 30 days than patients treated by surgeons with only five years of experience. Once surgeons had over 21 years of experience, the likelihood of readmission again began to increase. For example, patients treated by surgeons with 30 years of experience were 14% more likely to be readmitted within 30 days than patients treated by surgeons with 21 years of experience. A similar pattern was seen with regard to readmissions for infections.
Surgeon experience and length of stay. As surgeon experience increased, up to 10 years of experience, length of stay decreased. Length of stay increased, however, for patients treated by surgeons with 10 to 25 years of experience and decreased for surgeons with more than 25 years of experience.

The top five reasons patients were readmitted for a hospital after CABG surgery were:
Reason for Readmission	Percent of Readmissions Within 7 days	Percent of Readmissions Within 30 days
Total charges for readmissions within 7 days and 30 days were over $25 million and $53 million, respectively.
Heart Failure	20.5%	19.6%
Infections	18.0%	23.4%
Other surgical complications	11.50%	8.2%
Heart rhythm irregularities	9.9%	8.8%
Respiratory and chest symptoms	5.3%	5.6%

Length of Stay and Readmissions

In general, patients with longer post-surgical lengths of stay were more likely to be readmitted within 7 or 30 days of CABG surgery. Patients with longer post-surgical lengths of stay were also more likely to be readmitted to the hospital for an infection than patients with shorter lengths of stay.

The Number of Hospital Affiliations

The percent of surgeons performing open-heart surgery in multiple hospitals has increased since 1995. In 2000, 47% of the surgeons performed open-heart surgery in more than one hospital; in 1995, this figure was 33%.
The number of hospitals in which a surgeon performed CABG surgery was a significant predictor of the likelihood of a patient being readmitted, after accounting for patient risk. Patients were more likely to be readmitted to the hospital after CABG surgery if they were treated by surgeons affiliated with more than one hospital. As the number of hospital affiliations rose, so did the likelihood of both 7-day and 30-day readmissions.