The financial implications of cardiac stress testing prior to abdominal aortic aneurysm repair

Most preoperative stress tests fail to comply with practice guideline indications and do not reduce cardiac events

BACKGROUND

There is wide variation in stress test utilization before major vascular surgery and adherence to practice guidelines is unclear. We defined rates of stress test compliance at our institution and led a quality improvement initiative to improve compliance with American Heart Association (ACC/AHA) guidelines.

METHODS

We implemented a stress testing order set in the electronic medical record at one tertiary hospital. We reviewed all patients who underwent elective, major vascular surgery in the 6 months before (Jan 1, 2022 - Jul 1, 2022) and 6 months after (Aug 1, 2022 - Jan 31, 2023) implementation. We studied stress test guideline compliance, changes in medical or surgical management, and major adverse cardiac events (MACE).

RESULTS

Before order set implementation, 37/122 patients (30%) underwent stress testing within the past year (29 specifically ordered preoperatively) with 66% (19/29) guideline compliance. After order set implementation, 50/173 patients (29%) underwent stress testing within the past year (41 specifically ordered preoperatively) with 80% (33/41) guideline compliance. In the pre- and postimplementation cohorts, stress testing led to a cardiovascular medication change or preoperative coronary revascularization in 24% (7/29) and 27% (11/41) of patients, and a staged surgery or less invasive anesthetic strategy in 14% (4/29) and 4.9% (2/41) of patients, respectively. All unindicated stress tests were surgeon-ordered and none led to a change in management. There was no change in MACE after order set implementation.

CONCLUSIONS

Electronic medical record-based guidance of perioperative stress testing led to a slight decrease in overall stress testing and an increase in guideline-compliant testing. Our study highlights a need for improved preoperative cardiovascular risk assessment prior to major vascular surgery, which may eliminate unnecessary testing and more effectively guide perioperative decision-making.

Size thresholds for repair of abdominal aortic aneurysms warrant reconsideration

BACKGROUND

The historical size threshold for abdominal aortic aneurysm (AAA) repair is widely accepted to be 5.5 cm for men and 5.0 cm for women. However, contemporary AAA rupture risks may be lower than historical benchmarks, which has implications for when AAAs should be repaired. Our objective was to use contemporary AAA rupture rates to inform optimal size thresholds for AAA repair.

METHODS

We used a Markov chain analysis to estimate life expectancy for patients with AAA. The primary outcome was AAA-related mortality. We estimated survival using Social Security Administration life tables and published contemporary AAA rupture estimates. For those undergoing repair, we modified survival estimates using data from the Vascular Quality Initiative and Medicare on complications, late rupture, and open conversion. We used this model to estimate the AAA repair size threshold that minimizes AAA-related mortality for 60-year-old average-health men and women. We performed a sensitivity analysis of poor-health patients and 70- and 80-year-old base cases.

RESULTS

The annual risk of all-cause mortality under surveillance for a 60-year-old woman presenting with a 5.0 cm AAA using repair thresholds of 5.5 cm, 6.0 cm, 6.5 cm, and 7.0 cm was 1.7%, 2.3%, 2.7%, and 2.8%, respectively. The corresponding risk for a man was 2.3%, 2.9%, 3.3%, and 3.4% for the same repair thresholds, respectively. For a 60-year-old average-health woman, an AAA repair size of 6.1 cm was the optimal threshold to minimize AAA-related mortality. Life expectancy varied by <2 months for repair at sizes from 5.7 cm to 7.1 cm. For a 60-year-old average-health man, an AAA repair size of 6.9 cm was the optimal threshold to minimize AAA-related mortality. Life expectancy varied by <2 months for repair at sizes from 6.0 cm to 7.4 cm. Women in poor health, at various age strata, had optimal AAA repair size thresholds that were >6.5 cm, whereas men in poor health, at all ages, had optimal repair size thresholds that were >8.0 cm.

CONCLUSIONS

The optimal threshold for AAA repair is more nuanced than a discrete size. Specifically, there appears to be a range of AAA sizes for which repair is reasonable to minmized AAA-related mortality. Notably, they all are greater than current guideline recommendations. These findings would suggest that contemporary AAA size thresholds for repair should be reconsidered.

Patient, provider, and system-level factors associated with preoperative cardiac testing: A systematic review

BACKGROUND

Overuse of preoperative cardiac testing contributes to high healthcare costs and delayed surgeries. A large body of research has evaluated factors associated with variation in preoperative cardiac testing. However, patient, provider, and system-level factors associated with variation in testing have not been systematically studied.

OBJECTIVE

To conduct a systematic review to better delineate the patient, provider, and system-level factors associated with variation in preoperative cardiac testing.

METHODS

We included studies of an adult US population evaluating a patient, provider, or system-level factor associated with variation in preoperative cardiac testing for noncardiac surgery since 2012. Our search strategy used terms related to preoperative testing, diagnostic cardiac tests, and care variation with Ovid MEDLINE and Embase from inception through January 2023. We extracted study characteristics and factors associated with variation and qualitatively analyzed them. We assessed risk of bias using the Newcastle-Ottawa Scale and Evidence Project Risk of Bias tool.

RESULTS

Twenty-eight articles met inclusion criteria. Older age and higher comorbidity were strongly associated with higher-intensity testing. The evidence for provider and system-level covariates was weaker. However, there was strong evidence that a focus on primary care and away from preoperative clinic and cardiac consultations was associated with less testing and that interventions to reduce low-value testing can be successful.

CONCLUSIONS

There is significant interprovider and interhospital variation in preoperative cardiac testing, the correlates of which are not well-defined. Further work should aim to better understand these factors.

Increased Preoperative Stress Test Utilization is Not Associated With Reduced Adverse Cardiac Events in Current US Surgical Practice

OBJECTIVE

To measure the frequency of preoperative stress testing and its association with perioperative cardiac events.

BACKGROUND

There is persistent variation in preoperative stress testing across the United States. It remains unclear whether more testing is associated with reduced perioperative cardiac events.

METHODS

We used the Vizient Clinical Data Base to study patients who underwent 1 of 8 elective major surgical procedures (general, vascular, or oncologic) from 2015 to 2019. We grouped centers into quintiles by frequency of stress test use. We computed a modified revised cardiac risk index (mRCRI) score for included patients. Outcomes included in-hospital major adverse cardiac events (MACEs), myocardial infarction (MI), and cost, which we compared across quintiles of stress test use.

RESULTS

We identified 185,612 patients from 133 centers. The mean age was 61.7 (±14.2) years, 47.5% were female, and 79.4% were White. Stress testing was performed in 9.2% of patients undergoing surgery, and varied from 1.7% at lowest quintile centers, to 22.5% at highest quintile centers, despite similar mRCRI comorbidity scores (mRCRI>1: 15.0% vs 15.8%; P =0.068). In-hospital MACE was less frequent among lowest versus highest quintile centers (8.2% vs 9.4%; P <0.001) despite a 13-fold difference in stress test use. Event rates were similar for MI (0.5% vs 0.5%; P =0.737). Mean added cost for stress testing per 1000 patients who underwent surgery was $26,996 at lowest quintile centers versus $357,300 at highest quintile centers.

CONCLUSIONS

There is substantial variation in preoperative stress testing across the United States despite similar patient risk profiles. Increased testing was not associated with reduced perioperative MACE or MI. These data suggest that more selective stress testing may be an opportunity for cost savings through a reduction of unnecessary tests.