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Elderly patients who experience non-ST-segment-elevation myocardial infarction (NSTEMI) face higher long-term risk of death or recurrent ischemic events if they also have disease in other vascular territories, according to a study published online June 19, 2012, ahead of print in Circulation: Cardiovascular Quality and Outcomes. Paradoxically, these high-risk patients are less likely to receive early, aggressive treatment in accordance with current guidelines.

A research team led by Matthew T. Roe, MD, MHS, of Duke University Medical Center (Durham, NC), identified 34,205 patients with NSTEMI aged at least 65 years who enrolled in the CRUSADE registry between February 2003 and December 2006 and survived to hospital discharge. Details on these patients were linked to longitudinal data from the Centers for Medicare and Medicaid Services through 2008.

All patients were presumed to have CAD. The cohort was divided into 4 groups based on whether or not patients also had polyvascular disease, defined as prior peripheral arterial disease, cerebrovascular disease, or both:

• CAD alone (74.7%)
• CAD plus cerebrovascular (10.7%)
• CAD plus peripheral (11.5%)
• CAD plus peripheral and cerebrovascular (3.1%)

Less Catheterization, Intervention for Sicker Patients

During the index hospitalization, patients with polyvascular disease were less likely to receive early invasive management (catheterization ≤ 48 hours) or indeed any catheterization. They also underwent less revascularization (PCI or CABG) than those with CAD alone (table 1).

Table 1. In-Hospital Cardiac Procedures

Abbreviations: CAD, coronary artery disease; CVD, cerebrovascular disease; PAD, peripheral arterial disease.

Patients with polyvascular disease also had more diseased coronary vessels; those with disease in 3 arterial beds showed the highest rates of triple-vessel CAD.

A substantial proportion of patients in all groups failed to receive guideline-recommended medications such as statins, ACE inhibitors or angiotensin receptor blockers, and clopidogrel at discharge. Similarly, lifestyle-modification interventions such as smoking cessation counseling, referral for cardiac rehabilitation, and dietary counseling were less common among patients with polyvascular disease (P = 0.0006, P = 0.0002, and P  < 0.0001, respectively), especially those with both peripheral arterial and cerebrovascular disease.

More Disease Means Higher Mortality

Three years after the index NSTEMI, patients with CAD alone had a mortality rate of 33.2%. The incidence rose incrementally with increasing disease burden, to 49.2% for patients with peripheral disease and 52.1% for those with cerebrovascular disease, and to 58.5% among those with both.

Compared with patients with CAD alone, the adjusted mortality risk and the composite of all-cause death, readmission for MI, or readmission for ischemic stroke showed a similar pattern (table 2).

Table 2. Adjusted Risk of Long-term Outcomes by Vascular Bed Involvement

Abbreviations: CAD, coronary artery disease; CVD, cerebrovascular disease; PAD, peripheral arterial disease.

“Doctors have long appreciated that patients with more aggressive disease, as represented by the involvement of multiple vascular beds, tend to have worse prognoses,” Harlan M. Krumholz, MD, SM, of the Yale School of Medicine (New Haven, CT), told TCTMD in a telephone interview. “This work helps quantify what that additional risk is.”

Risk-Treatment Paradox Rears Its Head

The findings are in line with the so-called risk-treatment paradox, Dr. Krumholz observed. “Somehow people who are at greatest risk tend not to get as much treatment,” he said. “Maybe the development of these quantitative risk models will make that paradox clear to us in real time.”

Dr. Krumholz noted that sicker patients do have higher procedural risk, and that procedures can be more complicated. “Physicians tend to be risk averse; they don’t want to cause problems,” he said. “And yet even though these patients have a higher risk of complications, they gain a bigger net benefit from the procedure.

The current findings “help put the risk versus benefit in perspective,” he added.

Commenting on the suboptimal use of guideline-recommended therapies in the study period, which ended in 2006, Dr.  Krumholz said, “Every year it looks like treatment rates are improving. But the risk-treatment paradox persists, and we’ve got to find ways to understand and address it better.”

In a telephone interview with TCTMD, Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), agreed that the paradox seems to be at play in management of this older, very high-risk population.

But Dr. Kirtane cautioned that the limited information available from registries makes it difficult to distinguish between patients who were at high risk and those whose disease was so advanced that it precluded intervention. “I don’t think we can jump to the conclusion that doctors were discriminating against the sickest patients,” he said.

Peripheral Disease Merits Focus

Dr. Kirtane noted that registries such as CRUSADE help improve care by feeding data back to hospitals regarding how well they are managing these patients.

Nonetheless, numerous studies have shown that peripheral vascular disease is often underdiagnosed and undertreated, he added. “That’s important not just from the standpoint of the vascular disease itself but from the standpoint of the patients’ risk for future cardiovascular mortality.

“Peripheral vascular disease patients are at the highest risk and have the most to gain from treatment, so anything we can do to identify them early and use guideline-based therapy would be beneficial,” Dr. Kirtane concluded.

Study Details

Overall, patients with polyvascular disease were more likely to have multiple ischemic risk factors such as diabetes, hypertension, prior MI or CABG, and renal insufficiency. Moreover, the prevalence of these risk factors was higher among patients who had both cerebrovascular and peripheral disease compared with those who had either condition alone.

Prior peripheral disease was defined as history of claudication, amputation for arterial insufficiency, vascular reconstruction, bypass surgery or percutaneous intervention to the extremities, documented aortic aneurysm, or positive noninvasive test. Prior cerebrovascular disease was defined as history of stroke.

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