The role of digital angiography in the evaluation of coronary artery disease

The prognostic significance of SYNTAX score after early percutaneous transluminal coronary angioplasty for acute ST elevation myocardial infarction

INTRODUCTION

SYNergy between percutaneous coronary intervention (PCI) with TAXUS and Cardiac Surgery (SYNTAX) score, which is based on the characteristics of atherosclerotic lesions and the complexity of coronary artery anatomy, is useful for choosing an intervention strategy, but its prognostic significance for acute ST elevation of myocardial infarction (STEMI) remains unknown. This study aimed to redress this issue.

METHODS

Our observational study included 151 consecutive patients admitted for acute STEMI who underwent primary PCI between January 1, 2008 and December 31, 2009. The primary endpoint for analysis was 30-day cardiac death.

RESULTS

Among the 151 patients, cardiac death occurred in 10 (7%) within 30 days. After the first month, five patients died of non-cardiac causes, but no cardiac death occurred. Multivariate analysis showed that SYNTAX score (odds ratio [OR], 13.79, 95% confidence interval [CI], 1.24-153.38; p=0.033) and a symptom onset-to-therapy time interval >4 h (OR, 11.13; 95% CI, 1.08-114.42; p=0.043) were independent risk factors for 30-day mortality. The SYNTAX score cut-off for discriminating low and high risk was 22.

CONCLUSIONS

SYNTAX score is an independent predictor of short-term cardiac mortality in patients with acute STEMI.

Coronary score adds prognostic information for patients with acute coronary syndrome

BACKGROUND

The aim of the present study was to explore the association of 3 coronary scores with major adverse cardiovascular events (MACE) in patients with acute coronary syndrome (ACS).

METHODS AND RESULTS

The 958 consecutive patients with ACS were followed up until either MACE or 31(st) December 2008 occurred; 257 patients reached clinical endpoints. Cox regression analysis demonstrated that the Gensini score was associated with 90-day MACE (relative risk (RR) 1.021, P=0.004), 6-month MACE (RR 1.021, P<0.001), 1-year MACE (RR 1.017, P=0.002), and MACE during follow-up (RR 1.010, P=0.040). Leaman score was associated with 90-day MACE (RR 1.094, P=0.014), 6-month MACE (RR 1.098, P=0.002), and 1-year MACE (RR 1.074, P=0.009). The logistic regression analysis demonstrated that the Gensini score (odds ratio (OR) 1.037, P=0.001), Leaman score (OR 1.165, P=0.007) and American College of Cardiology/American Heart Association (ACC/AHA) score (OR 1.235, P=0.025) were all associated with cardiogenic death.

CONCLUSIONS

The Gensini score provides more valuable prognostic information on cardiovascular risk than either the Leaman or ACC/AHA score in patients with ACS.

Impact of various compression rates on interpretation of digital coronary angiograms

According to the ACC/ACR/NEMA/ESC-guidelines, digital techniques should be replaced by cinefilm for coronary angiography. The ad hoc group of experts recently chose CD-R (CD recordable) as transport media and the JPEG standard for image compression. To avoid a possible loss of image quality, the guidelines allow a maximal data compression of only 2:1. This, however, leads to a considerable limitation: coronary angiograms cannot be viewed in real-time directly from CD. Since the possible influence of higher compression rates on image quality of coronary angiograms had not been investigated in a controlled study, we evaluated 8 various compression rates (ranging from 5:1 to 43:1) according to a prospective, randomized and blinded protocol. Four independent observers assessed 1440 angiograms using a semiquantitative score. We found that angiograms with a compression rate of 5:1 and 6:1 did not lead to a clinically relevant deterioration of image quality, whereas 11:1 was still acceptable, but 43:1 becomes unacceptable. Since no clinically relevant loss of information at a compression rate of 6:1 was experienced in our study, a modification of the ACC/ACJ/NEMA/ESC-guidelines allowing higher compression rates should be considered.

Parametric assessment of myocardial perfusion during interventional cardiac catheterization by means of X-ray densitometry-short-and long-term results

X-ray densitometric evaluation of digital subtraction angiocardiograms allows an assessment of myocardial perfusion by means of the parameter 'MEAN RISE TIME' (MRT), defined as the time from the onset of local myocardial contrast medium opacification to the point of maximum opacification. Best results are obtained when the response of that parameter is compared before and after stimulation of coronary flow by papaverine. A prolongation of this parameter, especially after papaverine, was indicative of an impairment of myocardial perfusion, when compared to the results of TL-201 scintigraphy. In 50 patients with single vessel coronary artery disease the results of MRT pre and post papaverine before and after coronary angioplasty, as well as after 6 months were evaluated for 204 post-stenotic regions-of-interest. Before angioplasty papaverine induced a significant prolongation of post-stenotic MRT was measured 2.3 s +/- 0.9 s vs 3.1s +/- 0.8s; p less than 0.01), while after successful angioplasty post-stenotic MRT was measured significantly shorter after stimulation of coronary flow (2.6s +/- 1.0s vs. 1.9s +/- 0.9s; p less than 0.01). This indicated an improvement in myocardial perfusion. Nevertheless, 16/50 patients still presented pathological results of post-stenotic MRT after papaverine, although angioplasty was regarded successful. These patients presented a markedly higher rate of restenosis (14/16 patients after 6 months), a higher rate of dissections at the dilation site and a higher rate of dilated vessels, supplying myocardial areas after a Q-wave myocardial infarction. Thus, these results demonstrate the additional information about the short-and long-term outcome of an angioplasty procedure by densitometric myocardial perfusion analysis.

Translational motion compensation for coronary angiogram sequences

A method of compensating for the lag of the video cameras typically used in angiographic systems is presented for use in sequences of digitized X-ray images. The lag effect is reduced by a straightforward weighted subtraction, which has the undesirable side effect of increasing noise. By superimposing several lag-corrected and appropriately shifted images, however, the signal-to-noise ratio can be restored. The algorithm uses the phase-correlation method to measure the two-dimensional shift of a mobile coronary arterial structure. Processing is confined to a rectangular area of interest (AOI), which encloses a feature of clinical significance. The differences of the phases of the Fourier transforms of two frames is computed, combined with an appropriate filter, and inverse Fourier-transformed to produce a phase-correlation image. The vector separation from the origin of image space of the peak of the phase-correlation image is the estimate of the shift of the artery's position in the second frame as compared to the first. The isolation of the AOI from the surrounding image is achieved by the application of a window and correction for any linear trend in the background intensity.

Comparison of simultaneously performed digital and film-based angiography in assessment of coronary artery disease

This study compared digital angiography (Digital) to conventional cineangiography (Cine) for the diagnosis and quantification of coronary artery disease. Digital and Cine were obtained simultaneously under identical radiographic conditions during routine coronary arteriography. Using visual inspection and manual calipers, four independent observers identified 131 stenoses in 18 patients with multivessel coronary disease. There was no difference in interobserver variability between Digital and Cine during multiple subgroup analyses. Overall, Digital yielded significantly greater estimates of stenosis severity than did either of two separate Cine observations (p less than 0.0001; average difference, 6.25%), but the differences fell below the level of statistical significance when only the group of stenoses 50% or greater were considered. Digital and Cine correlated well for the assessment of stenosis severity (r = 0.88), but linear regression comparisons of multiple subgroups consistently indicated modest overestimation of Cine by Digital. Smaller vessels, branch vessels, and mild lesions increased the likelihood of overestimation by Digital. Digital was highly sensitive for identification of clinically relevant stenoses, but less specific and less predictive than a second observation of Cine. Our results indicate that Digital and Cine are not interchangeable imaging techniques and that potential differences must be considered when Digital is used for clinical decision making.