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Archive for March, 2012

CT Angiography shows incremental prognostic benefit

18 Mar, 12 | by Alistair Lindsay

Recently evidence has emerged suggesting the prognostic value of CT coronary angiography (CTCA), however whether it can provide extra information over and above routine clinical workup – including exercise treadmill testing – remains uncertain.  Dedic et al. determined to answer this question in patients with stable chest pain and suspected coronary artery disease (CAD).

The study enrolled 471 patients who underwent exercise ECG testing and CTCA, with exercise ECG tests being classified as either normal, ischaemic, or non diagnostic.  The primary outcome measure was a major adverse cardiac event (MACE), defined either as cardiac death, nonfatal myocardial infarction, or unstable angina requiring hospitalization and revascularization (beyond 6 months). Univariable and multivariable Cox regression analysis was used to determine the prognostic values, while clinical impact was assessed with the net reclassification improvement metric.

Over a mean follow-up of 2.6 years 44 MACEs occurred in 30 patients.  The presence of coronary calcification (hazard ratio [HR], 8.22 ), obstructive CAD (HR, 6.22), and nondiagnostic stress test results (HR, 3.00) were univariable predictors of MACEs. In the multivariable model, CT angiography findings (HR, 5.0) and nondiagnostic exercise ECG results (HR, 2.9) remained independent pre-dictors of MACEs. CT angiography findings showed incremental value beyond clinical predictors and stress testing (P <.001), whereas coronary calcium scores did not have further incremental value (P = .40).

Conclusions:

This study shows again that CT angiography findings are a strong predictor of future adverse events, in this study showing incremental value over clinical predictors, stress testing, and coronary calcium scores.

  • Dedic A, Genders TSS, Ferket BS et al.  Stable Angina Pectoris: Head-to- Head Comparison of Prognostic Value of Cardiac CT and Exercise Testing.  Radiology 2011;261:428-436.

Gender differences in myocardial infarction

16 Mar, 12 | by Alistair Lindsay

In general, women present to hospital with symptoms and signs of coronary artery disease at a later age than males; furthermore, they often present with atypical symptoms.  While a large amount of work has been directed towards examining sex differences in mortality, few studies have taken into account age difference when doing so.

In this observational study from the US National Registry of Myocardial Infarction between 1994 and 2006, Canto et al. examined predictors of myocardial infarction (MI) presentation without chest pain, and the relationship between age, gender, and hospital mortality.  The authors found that far more women than men presented with an MI without any chest pain (42.0% [95% CI, 41.8%-42.1%] vs 30.7% [95% CI, 30.6%-30.8%]; P < .001). They also noted a  significant interaction between age and sex with chest pain at presentation, with a larger sex difference seen in younger patients, which became attenuated with advancing age.  Younger women presenting without chest pain had greater hospital mortality than younger men without chest pain, and these sex differences decreased or even reversed with advancing age.  The 3-way interaction between sex, age, and chest pain on mortality was significant (P < .001).

Conclusion:

This study found that women were more likely than men to present with an MI without chest pain, and that a higher mortality was seen compared to men within the same age group.  However, it also found that these changes were attenuated with increasing age.

  • Canto JG, Rogers WJ, Goldberg RJ, et al.  Association of Age and Sex With Myocardial Infarction Symptom Presentation and In-Hospital Mortality.  JAMA 2012; 307(8):813-822.

No cardiac benefit of vitamin D in CKD

4 Mar, 12 | by Alistair Lindsay

There is a renewed interest in the role of vitamin D in cardiovascular disease, largely due to observational studies suggesting a link between vitamin D deficiency and cardiovascular outcomes.  Moreover, vitamin D receptors have been found on vascular smooth muscle, and endothelial cells.  Given the vitamin D deficiency that commonly effects patients with chronic kidney disease (CKD), the purpose of this study was to examine whether supplementation with vitamin D could improve cardiac function and outcomes in patients with CKD.

The PRIMO (Paricalcitol Capsule Benefits in Renal Failure–Induced Cardiac Morbidity) trial, was an investigator-initiated, industry-sponsored, multinational, double-blind, randomized placebo-controlled trial, to test the hypothesis that 48-week treatment with paricalcitol (19-nor-1,25-[OH]2 vitamin D2) could reduce left ventricular mass, improve diastolic function, reduce CVD events, and improve cardiac biomarkers in patients with left ventricular hypertrophy (LVH) and CKD.  All study participants were randomly assigned to receive oral paricalcitol, 2 μg/d (n =115), or matching placebo (n = 112).  The main outcomes measures were the change in left ventricular mass index over 48 weeks as assessed by cardiovascular magnetic resonance imaging. Secondary end points included echocardiographic changes in left ventricular diastolic function.  Overall 227 patients were recruited.

Initiially, treatment with paricalcitol was seen to reduce parathyroid hormone levels within 4 weeks and maintained levels within the normal range throughout the study duration. However at 48 weeks, the change in left ventricular mass index did not differ between treatment groups (paricalcitol group, 0.34 g/m2.7 [95% CI, −0.14 to 0.83 g/m2.7] vs placebo group, −0.07 g/m2.7 [95% CI, −0.55 to 0.42 g/m2.7]). Furthermore, doppler measures of diastolic function including peak early diastolic lateral mitral annular tissue velocity (paricalcitol group, −0.01 cm/s [95% CI, −0.63 to 0.60 cm/s] vs placebo group, −0.30 cm/s [95% CI, −0.93 to 0.34 cm/s]) did not differ. However, it was noted that cardiac hospitalizations were slightly lower in the paricalcitol group as compared with the placebo group, and that increases in plasma B-type natriuretic-peptide (BNP) were less marked also.  But paricalcitol also increased serum creatinine and decreased creatinine-based measures of estimated glomerular filtration rate (eGFR), and an increase in adverse events was seen due to episodes of hypercalcaemia in the treatment group.

Conclusions:

In this multi-centre study, vitamin D supplementation in patients with CKD did not lead any structural improvements in cardiac function after 48 weeks.  Although a link seems to exist between cardiovascular disease and vitamin D levels, results from trials of vitamin D supplementation have to date been mixed.

  • Thadhani R,  Appelbaum E, Pritchett Y et al.  Vitamin D Therapy and Cardiac Structure and Function in Patients With Chronic Kidney Disease.  JAMA 2012;307(7):674-684. doi:10.1001/jama.2012.120

Intracoronary abciximab offers no extra benefit

4 Mar, 12 | by Alistair Lindsay

Despite the introduction of primary angioplasty programmes for patients with acute ST-elevation myocardial infarction (STEMI), up to 70% of patients have impaired myocardial tissue perfusion even after successful treatment.  As intracoronary delivery of abciximab results in much higher concentrations within the coronary artery when compared to intravenous administration, it is logical to propose that this could increase platelet inhibition, displacement of platelet-bound fibrin, and thrombi dissolution, which in turn could decrease distal embolisation and increase myocardial tissue perfusion.n  Should intracoronary injection of abciximab therefore be routine practice during primary percutaneous coronary intervention?

In the Abciximab Intracoronary versus intravenous Drug Application in ST-Elevation Myocardial Infarction (AIDA STEMI) open-label, multicentre trial 1032 patients presenting within 12 hours of STEMI were randomly assigned to receive intracoronary abciximab and 1033 to receive intravenous abciximab. At 90 days after randomisation, the incidence of the primary efficacy endpoint, a composite of all-cause mortality, reinfarction, and new heart failure was similar in the intracoronary group compared with the intravenous group (7.0% vs 7.6%, OR 0.91, 95% CI 0.64–1.28, p=0.58).  However, fewer patients in the intracoronary group had new congestive heart failure (2.4% vs 4.1%; OR 0.57, CI 0.33–0.97, p=0.04) despite similar angiographic appearances and ejection fractions. Bleeding complications did not differ between the two groups and no complications were recorded during intracoronary delivery.  However, a lower than expected event rate in the trial may mean that it was underpowered to detect significant differences between the groups.

Conclusions:

In the setting of primary PCI intracoronary abciximab bolus administration is safe but was not associated with a difference in the combined endpoint of death, reinfarction, or congestive heart failure.

Reference:

  1. Thiele H, Wöhrle J, Hambrecht R, Rittger H, Birkemeyer R, Lauer B, Neuhaus P,  Brosteanu O, Sick P, Wiemer M, Kerber S, Kleinertz K, Eitel I, Desch S, Schuler G. Intracoronary versus intravenous bolus abciximab during primary percutaneous coronary intervention in patients with acute ST-elevation myocardial infarction:  a randomised trial. Lancet. 2012 Feb 20. [Epub ahead of print]

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