Dave Chua

Predictors of late cardiac events following treatment with Sr-90 β-irradiation for instent restenosis

BACKGROUND Intracoronary radiation therapy (IRT) with Sr-90 using the Novoste Beta-Cath system has been shown to be an effective therapy for instent restenosis (ISR), but the temporal occurrence of cardiac events and the predictors of late complications require further investigation. METHODS We analyzed the demographics, lesion characteristics and clinical outcomes of 138 consecutive patients with ISR treated with IRT from September 1998 to March 2002. Major adverse cardiac events (MACE) were defined as death, myocardial infarction (MI) or target vessel revascularization (TVR). Characteristics of early (< or =8 months) and late (>8 months) failures were analyzed. RESULTS Thirty-two (23.1%) of 138 patients had MACE on follow-up; 25% (8/32) of failures occurred late after treatment with IRT. A comparison of the clinical and angiographic profile of early and late failures using univariate analysis indicates no correlations to late failure following IRT. Duration to failure after IRT was 14.25+/-3.69 months in the late group compared to 4.63+/-2.86 months in the early group (P<.001). CONCLUSIONS Late MACE after IRT with Sr-90 for ISR occur beyond the traditional period for clinical restenosis in 25% of cases and are difficult to predict. Further study is warranted to identify patients at risk for the development of late complications after IRT.

Angiotensin Receptor Blockade and Arterial Compliance in Chronic Kidney Disease: A Pilot Study

Background: Almost 20 million people in the US have chronic kidney disease (CKD). Cardiovascular disease and arterial wall abnormalities are common in this population. Because angiotensin II may have adverse effects on the arterial wall, we hypothesized that an angiotensin receptor blocker (ARB) would improve arterial compliance as compared with placebo in subjects with CKD. Methods: We performed a double-blinded, placebo-controlled pilot study in which 25 subjects with stages 2 or 3 CKD and proteinuria <1 g were randomized to either the ARB, eprosartan, or placebo and titrated to achieve a goal blood pressure (BP) <130/85 mm Hg. Arterial compliance was measured at baseline and at 8 weeks. Results: Baseline characteristics were similar between the groups and included mean estimated glomerular filtration rate 63 ± 14 ml/min/1.73 m2, heart rate 76 ± 10 beats/min, BP 142 ± 12/81 ± 8 mm Hg, 64% diabetic, 44% male, and 40% white, though subjects in the eprosartan group were younger (60 ± 12 vs. 70 ± 6 years, p = 0.01). There were no significant differences between the groups in large or small artery compliance measurements either at baseline or at 8 weeks, but there was a statistically significant improvement from baseline in small artery compliance in the eprosartan group (from median 2.5 ml/mm Hg × 100 [90% CI (1.1, 4.7)] to 4.0 ml/mm Hg × 100 [90% CI (1.9, 6.7)] (p = 0.01)) not seen in the placebo group. Conclusion: Use of an ARB to achieve recommended BP is associated with improved small artery compliance in people with CKD, though larger studies are needed to confirm these findings.

Diabetes and Chronic Kidney Disease: Tragedy and Challenge

Management of hypertension in diabetic nephropathy is challenging and generally requires a minimum of three different and complementary antihypertensive agents to achieve the recently recommended blood pressure (BP) goal of <130/80 mm Hg in order to reduce cardiovascular (CV) risk and preserve kidney function. Commonly used antihypertensive combinations include an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker, agents that have compelling indications for use in diabetic renal disease, added to a diuretic, generally a thiazide-type agent. If additional therapy is required, either a beta-blocker or calcium antagonist may be added. Beta-blockers are particularly effective in people with a high sympathetic drive, i.e. high pulse rates, to lower BP and reduce CV risk while reducing proteinuria and slowing decline of kidney function. In light of this information, it is disturbing that a recent analysis of the NHANES III database indicates that only about 11% of people with diabetic kidney disease have achieved the target BP of <130/80 mm Hg. Recent data from Denmark demonstrate that focusing on total CV risk reduction among people with diabetes, including achievement of recommended BP and lipid goals along with the use of aspirin, exercise and a proper diet, can reduce the absolute risk of a CV event by 20% over less intensive treatment.

Visual assessment of procedural results following treatment with Sr-90 β-radiation for instent restenosis

BACKGROUND Visual assessment (VA) of postprocedural % diameter stenosis (DS) is used routinely in clinical practice to determine the adequacy of coronary intervention. Although VA has been shown to underestimate final %DS after balloon angioplasty compared to quantitative coronary angiography (QCA), the impact of this effect on clinical outcomes following treatment with intracoronary radiation therapy (IRT) with Sr-90 for instent restenosis (ISR) is unknown. METHODS To determine the effect of VA on the rate of major adverse cardiac events (MACEs) after IRT for ISR, we compared the clinical outcomes of 102 consecutive patients based on postprocedural %DS by QCA vs. %DS by VA. MACE was defined as death, M1 or need for target vessel revascularization (TVR). RESULTS MACE rates for the 102 consecutive patients grouped according to postprocedural %DS by QCA and VA were compared. The mean %DS by QCA was 30.7%, while the mean %DS by VA was 12.5%. The mean %DS by VA across the QCA subgroups were 13.67%, 10.71% and 13.37%, respectively (P = .244). Fifty-two patients (51.0%) had %DS > 30% by QCA with the highest MACE percentage occurring in this subgroup. CONCLUSION VA underestimated the %DS compared to QCA, and it was associated with worse MACE following treatment with Sr-90 for ISR.