Circ: Blacks at higher risk for stent thrombosis after DES
African-Americans may have more of a risk of developing life-threatening thrombosis after receiving drug-eluting stents (DES); however, socioeconomic status was independent of stent thrombosis, according to the results of a study published in the Aug. 31 issue of Circulation.
“It has been suggested that black race predicts stent thrombosis after DES implantation,” the authors wrote. “Whether socioeconomic status or comorbid conditions confound the contribution of black race to the development of stent thrombosis is unclear.”
To evaluate incidences of early, late and very late stent thrombosis in the black population, Sara D. Collins, MD, of the Washington Hospital Center in Washington, D.C., and colleagues compared 1,594 black patients who underwent DES implantations with outcomes of 5,642 non-black patients.
Of the patient cohort, 65.7 percent were male and all had an average age of 65 years.
In the patient cohort, researchers found that median household incomes (per $10,000) were significantly lower in the black patient arm compared to the non-black population, $44,197 versus $60,838, respectively.
In addition, black patients were more likely to be younger and had a greater history of hypertension, diabetes mellitus, chronic renal insufficiency and congestive heart failure.
Patients underwent PCI at a single high-volume PCI center between April 2003 and December 2008, and researchers assessed outcomes of stent thrombosis, Q-wave MI and target vessel revascularization (TVR) at 30 days, 12, 24, and 36 months.
Timing of stent thrombosis was classified as early, late or very late (less than 30 days, 30 days to one year, and greater than one year post-PCI).
Of the 7,246 patients, there were 13,135 total lesions. Of the patients who presented with stent thrombosis, 82 received sirolimus-eluting stents (Cypher, Cordis), 26 received paclitaxel-eluting stents (Taxus, Boston Scientific), one received a zotarolimus-eluting stent (Endeavor, Medtronic) and two received a combination sirolimus/paclitaxel stents.
Results showed that the rates of stent thrombosis were 0.83 percent (early) and 1.11 percent for late stent thrombosis at one year. At two and three years, rates of late stent thrombosis were 1.46 and 1.76 percent, respectively.
Cumulative rates of late stent thrombosis were 0.24 percent per year (30 days to one year). These rates increased to 0.36 percent per year from one to two years.
The researchers found that rates of early stent thrombosis at 30 days were 1.71 percent for the black population compared with 0.59 percent for the non-black population. These rates at one year were reported to be 2.25 percent and 0.79 percent, respectively. Late stent thrombosis for the aforementioned groups at two years and three years were 2.78 percent versus 1.09 percent, and 3.67 percent versus 1.25 percent, respectively.
Additionally, blacks experienced higher incidences of all-cause mortality compared to the non-black population at 36 months, 24.9 percent versus 13.1 percent, respectively. The rates of death/MI were 29.8 percent and 15.9 percent, respectively.
The results also showed that 87.5 percent of blacks were taking clopidogrel (Plavix, Bristol-Myers Squibb/Plavix) at the time of stent thrombosis compared to 77.8 percent of the non-black population.
Black race, diabetes, congestive heart failure and previous PCI were found to be independent predictors of early stent thrombosis; however, the authors said, “On further examination, black race emerged as the strongest independent predictor of late stent thrombosis (defined as more than 30 days), whereas history of diabetes mellitus was no longer predictive after 30 days.
“Black race is an independent predictor of stent thrombosis even when accounting for potential confounders such as socioeconomic status and comorbidities,” which has been previously associated with worse outcomes after cardiac revascularization, the authors wrote.
“This is the first study to demonstrate black race as an independent predictor of stent thrombosis after DES implantation,” the authors wrote. “Because our analysis adjusts for traditional variables associated with racial disparities in healthcare, further mechanisms such as genetic polymorphisms and responsiveness to antiplatelet therapy must be pursued.”
“It has been suggested that black race predicts stent thrombosis after DES implantation,” the authors wrote. “Whether socioeconomic status or comorbid conditions confound the contribution of black race to the development of stent thrombosis is unclear.”
To evaluate incidences of early, late and very late stent thrombosis in the black population, Sara D. Collins, MD, of the Washington Hospital Center in Washington, D.C., and colleagues compared 1,594 black patients who underwent DES implantations with outcomes of 5,642 non-black patients.
Of the patient cohort, 65.7 percent were male and all had an average age of 65 years.
In the patient cohort, researchers found that median household incomes (per $10,000) were significantly lower in the black patient arm compared to the non-black population, $44,197 versus $60,838, respectively.
In addition, black patients were more likely to be younger and had a greater history of hypertension, diabetes mellitus, chronic renal insufficiency and congestive heart failure.
Patients underwent PCI at a single high-volume PCI center between April 2003 and December 2008, and researchers assessed outcomes of stent thrombosis, Q-wave MI and target vessel revascularization (TVR) at 30 days, 12, 24, and 36 months.
Timing of stent thrombosis was classified as early, late or very late (less than 30 days, 30 days to one year, and greater than one year post-PCI).
Of the 7,246 patients, there were 13,135 total lesions. Of the patients who presented with stent thrombosis, 82 received sirolimus-eluting stents (Cypher, Cordis), 26 received paclitaxel-eluting stents (Taxus, Boston Scientific), one received a zotarolimus-eluting stent (Endeavor, Medtronic) and two received a combination sirolimus/paclitaxel stents.
Results showed that the rates of stent thrombosis were 0.83 percent (early) and 1.11 percent for late stent thrombosis at one year. At two and three years, rates of late stent thrombosis were 1.46 and 1.76 percent, respectively.
Cumulative rates of late stent thrombosis were 0.24 percent per year (30 days to one year). These rates increased to 0.36 percent per year from one to two years.
The researchers found that rates of early stent thrombosis at 30 days were 1.71 percent for the black population compared with 0.59 percent for the non-black population. These rates at one year were reported to be 2.25 percent and 0.79 percent, respectively. Late stent thrombosis for the aforementioned groups at two years and three years were 2.78 percent versus 1.09 percent, and 3.67 percent versus 1.25 percent, respectively.
Additionally, blacks experienced higher incidences of all-cause mortality compared to the non-black population at 36 months, 24.9 percent versus 13.1 percent, respectively. The rates of death/MI were 29.8 percent and 15.9 percent, respectively.
The results also showed that 87.5 percent of blacks were taking clopidogrel (Plavix, Bristol-Myers Squibb/Plavix) at the time of stent thrombosis compared to 77.8 percent of the non-black population.
Black race, diabetes, congestive heart failure and previous PCI were found to be independent predictors of early stent thrombosis; however, the authors said, “On further examination, black race emerged as the strongest independent predictor of late stent thrombosis (defined as more than 30 days), whereas history of diabetes mellitus was no longer predictive after 30 days.
“Black race is an independent predictor of stent thrombosis even when accounting for potential confounders such as socioeconomic status and comorbidities,” which has been previously associated with worse outcomes after cardiac revascularization, the authors wrote.
“This is the first study to demonstrate black race as an independent predictor of stent thrombosis after DES implantation,” the authors wrote. “Because our analysis adjusts for traditional variables associated with racial disparities in healthcare, further mechanisms such as genetic polymorphisms and responsiveness to antiplatelet therapy must be pursued.”