Jose Baptista

Ischemia-related lesion characteristics in patients with stable or unstable angina. A study with intracoronary angioscopy and ultrasound.

BACKGROUND Postmortem-derived findings support the common beliefs that lipid-rich coronary plaques with a thin, fibrous cap are prone to rupture and that rupture and superimposed thrombosis are the primary mechanisms causing acute coronary syndromes. In vivo imaging with intracoronary techniques may disclose differences in the characterization of atherosclerotic plaques in patients with stable or unstable angina and thus may provide clues to which plaques may rupture and whether rupture and thrombosis are active. METHODS AND RESULTS We assessed the characteristics of the ischemia-related lesions with coronary angiography and intracoronary angioscopy and determined their compositions with intracoronary ultrasound in 44 patients with unstable and 23 patients with stable angina. The angiographic images were classified as noncomplex (smooth borders) or complex (irregular borders, multiple lesions, thrombus). Angioscopic images were classified as either stable (smooth surface) or thrombotic (red thrombus). The ultrasound characteristics of the lesion were classified as poorly echo-reflective, highly echo-reflective with shadowing, or highly echo-reflective without shadowing. There was a poor correlation between clinical status and angiographic findings. An angiographic complex lesion (n = 33) was concordant with unstable angina in 55% (24 of 44); a noncomplex lesion (n = 34) was concordant with stable angina in 61% (14 of 23). There was a good correlation between clinical status and angioscopic findings. An angioscopic thrombotic lesion (n = 34) was concordant with unstable angina in 68% (30 of 44); a stable lesion (n = 33) was concordant with stable angina in 83% (19 of 23). The ultrasound-obtained composition of the plaque was similar in patients with unstable and stable angina. CONCLUSIONS Angiography discriminates poorly between lesions in stable and unstable angina. Angioscopy demonstrated that plaque rupture and thrombosis were present in 17% of stable angina and 68% of unstable angina patients. Currently available ultrasound technology does not discriminate stable from unstable plaques.

Quantitative coronary angiography in the estimation of the functional significance of coronary stenosis: Correlations with dobutamine-atropine stress test

OBJECTIVES The purpose of this study was to determine the predictive value of quantitative coronary angiography in the assessment of the functional significance of coronary stenosis as judged from the development of left ventricular wall motion abnormalities during dobutamine-atropine stress echocardiography. BACKGROUND Coronary angiography is the reference method for assessment of the accuracy of noninvasive diagnostic imaging techniques to detect the presence of significant coronary stenosis. However, use of arbitrary cutoff criteria for the interpretation of angiographic data may considerably influence the true diagnostic accuracy of the technique investigated. METHODS Thirty-four patients without previous myocardial infarction and with single-vessel coronary stenosis were studied with both quantitative angiography and dobutamine-atropine stress echocardiography. Two different techniques of quantitative angiographic analysis--edge detection and videodensitometry--were used for measurement of minimal lumen diameter, percent diameter stenosis and percent area stenosis. Two-dimensional echocardiographic images were collected during incremental doses of intravenous dobutamine and later analyzed using a 16-segment left ventricular model. Angiographic cutoff criteria were derived from receiver-operating curves to define the functional significance of coronary stenosis on the basis of dobutamine-atropine stress echocardiography. RESULTS The angiographic cutoff values with the best predictive value for the development of left ventricular wall motion abnormalities during dobutamine-atropine stress echocardiography were minimal lumen diameter of 1.07 mm, percent diameter stenosis of 52% and percent area stenosis of 75%. Minimal lumen diameter was found to have the best predictive value for a positive dobutamine stress test (odds ratio 51, sensitivity 94%, specificity 75%). CONCLUSIONS Automated quantitative angiographic measurement of minimal lumen diameter is a practical and useful index for determining both the anatomic and functional significance of coronary stenosis, and a value of 1.07 mm is the best predictor for a positive dobutamine stress test.

Impact of plaque morphology and composition on the mechanisms of lumen enlargement using intracoronary ultrasound and quantitative angiography after balloon angioplasty

Limited information is provided by angiography on plaque morphology and composition before balloon angioplasty. Identification of plaques associated with reduced lumen gain or a high complication rate may provide the rationale for using alternative revascularization devices. We studied 60 patients with quantitative angiography and intracoronary ultrasound (ICUS) before and after balloon dilation. Angiography was used to measure transient wall stretch and elastic recoil. ICUS was used to investigate the mechanisms of lumen enlargement among different plaque compositions and in the presence of a disease-free wall (minimal thickness < or = 0.6 mm). Compared with ultrasound, angiography underestimated the presence of vessel calcification (13% vs 78%), lumen eccentricity (35% vs 62%), and wall dissection (32% vs 57%). ICUS measurements showed that balloon angioplasty increased lumen area from 1.82 +/- 0.51 to 4.81 +/- 1.43 mm2. Lumen enlargement was the result of the combined effect of an increase in the total cross-sectional area of the vessel (wall stretching, 43%) and of a reduction in the area occupied by the plaque (plaque compression or redistribution, 57%). Vessels with a disease-free wall had smaller lumen gain than other types of vessels (2.13 +/- 1.26 vs 3.59 +/- mm2, respectively, p < 0.01). Wall stretching was the most important mechanism of lumen enlargement in vessels with a disease-free wall (79% vs 37% in the other vessels). Angiography revealed a direct correlation between temporary stretch and elastic recoil that was responsible for 26% of the loss of the potential lumen gain. Thus, lumen enlargement after balloon angioplasty is the combined result of wall stretch and plaque compression or redistribution. ICUS indicates that vessels with a remnant arc of disease-free wall are dilated mainly by wall stretching compared with other types of vessels and are associated with a smaller lumen gain.

Significance of Automated Stenosis Detection During Quantitative Angiography Insights Gained From Intracoronary Ultrasound Imaging

BACKGROUND Automated stenosis analysis is a common feature of commercially available quantitative coronary angiography (QCA) systems, allowing automatic detection of the boundaries of the stenosis, interpolation of the expected dimensions of the coronary vessel at the point of obstruction, and angiographically derived estimation of atheromatous plaque size. However, the ultimate meaning of this type of analysis in terms of the degree of underlying atherosclerotic disease remains unclear. We investigated the relationship between stenosis analysis performed with QCA and the underlying degree of atherosclerotic disease judged by intracoronary ultrasound (ICUS) imaging. METHODS AND RESULTS In 40 coronary stenoses, automated identification of the sites of maximal luminal obstruction and the start of the stenosis was performed with QCA by use of curvature analysis of the obtained diameter function. Plaque size at these locations also was estimated with ICUS, with an additional ICUS measurement immediately proximal to the start of the stenosis. Crescentlike distribution of plaque, indicating an atheroma-free arc of the arterial wall, was recorded. At the site of the obstruction, total vessel area measured with ICUS was 16.65 +/- 4.04 mm2, whereas an equivalent measurement obtained from QCA-interpolated reference dimensions was 7.48 +/- 3.30 mm2 (P = .0001). Plaque area derived from QCA data was significantly less than that calculated from ICUS (6.32 +/- 3.21 and 13.29 +/- 4.22 mm2, respectively; mean difference, 6.92 +/- 4.43 mm2; P = .0001). At the start of the stenosis identified by automated analysis, ICUS plaque area was 9.38 +/- 3.17 mm2, and total vessel area was 18.77 +/- 5.19 mm2 (50 +/- 11% total vessel area stenosis). The arterial wall presented a disease-free segment in 28 proximal locations (70%) but in only 5 sites (12%) corresponding to the start of the stenosis and none at the obstruction (P = .0001). At the site of obstruction, all vessels showed a complete absence of a disease-free segment, and the atheroma presented a cufflike or all-around distribution with a variable degree of eccentricity. CONCLUSIONS At the site of maximal obstruction, QCA underestimated plaque size as measured with ICUS. Atherosclerotic disease was consistently present at the start of the stenosis and was used as a reference site by automated stenosis analysis. At the start of the stenosis, ICUS demonstrated a mean 50 +/- 11% total vessel area stenosis, with a characteristic loss of disease-free arcs of arterial wall present in proximal locations. Thus, the site identified by automated stenosis analysis as the start of the stenosis does not represent a disease-free site but rather the place where compensatory vessel enlargement fails to preserve luminal dimensions, a phenomenon that seems related to the observed loss of a remnant arc of normal arterial wall.

Angiographic, ultrasonic, and angioscopic assessment of the coronary artery wall and lumen area configuration after directional atherectomy : the mechanism revisited

The purpose of the present study was to use the complementary information of angiography, intravascular ultrasound, and intracoronary angioscopy before and after directional atherectomy to characterize the postatherectomy appearance of vessel wall contours and the mechanism of lumen enlargement. Directional coronary atherectomy aims at debulking rather than dilating a coronary artery lesion. The selective removal of the plaque may potentially minimize the vessel wall damage and lead to subsequent better late outcome. Whether plaque removal is the main mechanism of action has only to be assessed indirectly by angiography and warrants further investigation with detailed analysis of luminal changes and vessel wall damage by ultrasound and direct visualization with angioscopy. Twenty-six patients have been investigated by quantitative angiography, intravascular ultrasound, and intracoronary angioscopy (n = 19) before and after atherectomy. In addition, all retrieved specimens were microscopically examined. Ultrasound imaging showed an increase in lumen area from 1.95 +/- 0.70 mm2 to 7.86 +/- 2.16 mm2 at atherectomy. The achieved gain mainly resulted from plaque removal because plaque plus media area decreased from 18.16 +/- 4.47 mm2 to 13.13 +/- 3.10 mm2. Vessel wall stretching (i.e., change in external elastic lamina area) accounted for only 15% of lumen area gain. Luminal gain was higher in noncalcified (6.52 +/- 2.12 mm2) lesions than in lesions containing deeply located calcium (5.19 +/- 0.99 mm2) and lowest in superficially calcified lesions (5.41 +/- 2.41 mm2). Ultrasound imaging identified an atherectomy byte in 85% of the cases, whereas angioscopy revealed such a crevice in 74%. The complementary use of the three techniques revealed an underestimation of the presence of dissection/tear and new thrombus by angiography (10% and 4%) and ultrasound imaging (12% and 0%) compared with angioscopy (26% and 21%). The combined use of angiography, ultrasound, and angioscopy reveals that the postatherectomy luminal lining is not as regular and smooth as that seen by angiography. Luminal enlargement with atherectomy is achieved by plaque excision rather than arterial expansion.

Posição sobre suportes vasculares restaurativos transitórios coronários em Portugal

BACKGROUND Bioresorbable vascular scaffolds (BVS) were recently approved for percutaneous coronary intervention in Europe. The aim of this position statement is to review the information and studies on available BVS, to stimulate discussion on their use and to propose guidelines for this treatment option in Portugal. METHODS AND RESULTS A working group was set up to reach a consensus based on current evidence, discussion of clinical case models and individual experience. The evidence suggests that currently available BVS can produce physiological and clinical improvements in selected patients. There are encouraging data on their durability and long-term safety. Initial indications were grouped into three categories: (a) consensual and appropriate - young patients, diabetic patients, left anterior descending artery, long lesions, diffuse disease, and hybrid strategy; (b) less consensual but possible - small collateral branches, stabilized acute coronary syndromes; and (c) inappropriate - left main disease, tortuosity, severe calcification. CONCLUSION BVS are a viable treatment option based on the encouraging evidence of their applicability and physiological and clinical results. They should be used in appropriate indications and will require technical adaptations. Outcome monitoring and evaluation is essential to avoid inappropriate use. It is recommended that medical societies produce clinical guidelines based on high-quality registries as soon as possible.

Percutaneous revascularization strategies in saphenous vein graft lesions: Long-term results

AIMS Although half of saphenous vein grafts (SVGs) present obstructive atherosclerotic disease 10 years after implantation, controversy remains concerning the ideal treatment. Our aim was to compare percutaneous revascularization (PCI) options in SVG lesions, according to intervention strategy and type of stent. METHODS A retrospective single-center analysis selected 618 consecutive patients with previous bypass surgery who underwent PCI between 2003 and 2008. Clinical and angiographic parameters were analyzed according to intervention strategy - PCI in SVG vs. native vessel vs. combined approach - and type of stent implanted - drug-eluting (DES) vs. bare-metal (BMS) vs. both. A Cox regressive analysis of event-free survival was performed with regard to the primary outcomes of death, myocardial infarction (MI) and target vessel failure (TVF). RESULTS During a mean follow-up of 796±548 days the rates of death, MI and TVF were 10.9%, 10.5% and 29.5%, respectively. With regard to intervention strategy (74.4% of PCI performed in native vessels, 17.2% in SVGs and 8.4% combined), no significant differences were seen between groups (death p=0.22, MI p=0.20, TVF p=0.80). The type of stents implanted (DES 83.2%, BMS 10.2%, both 3.2%) also did not influence long-term prognosis (death p=0.09, MI p=0.11, TVF p=0.64). The implantation of DES had a favorable impact on survival (p<0.001) in the subgroup of patients treated in native vessels but not in SVG. CONCLUSIONS Among patients with SVG lesions, long-term mortality, MI and TVF were not affected by intervention options, except for the favorable impact on survival of DES in patients treated in native vessels.

Does coronary lumen morphology influence vessel cross-sectional area estimation? An in vitro comparison of intravascular ultrasound and quantitative coronary angiography

Over the last 10 years quantitative coronary angiography has clearly emerged as the gold standard coronary imaging modality. However, despite the objectivity and reproducibility of coronary luminal measurements provided by quantitative angiographic analysis systems, a number of important limitations have been identified through their application to interventional procedures [1]. In particular, complex coronary lesions (for example, thrombus containing or ulcerated lesions) or the modifications in luminal geometry caused by percutaneous interventions, may yield inaccurate and unreliable luminal measurements [1–6]. These pitfalls of quantitative coronary angiography have been highlighted in recent years through the emergent clinical application of intracoronary ultrasound and angioscopy. Intravascular ultrasound imaging itself continues to undergo rapid evolution and has been advanced by its proponents as having a superior capacity for demonstrating luminal morphology, especially after coronary interventions [7–9].

Progressão ultrarrápida de doença coronária ou placa instável não detetada

Coronary artery disease rarely manifests itself in the first decades of life, which explains why this population is underrepresented in clinical studies. The mechanisms and natural history of the disease seem to differ between this population and older patients. Recent studies suggest a more rapid disease progression in youth, presenting more unstable atherosclerotic plaques, although this correlation has yet to be proven. In this paper, we present the case of a 41-year-old man who presented with a non-ST elevation myocardial infarction, with percutaneous coronary intervention of the culprit lesion (70-90% lesion at bifurcation of the circumflex artery with the first marginal obtuse artery and a sub-occlusive lesion of the ramus intermedius). There was also a non-significant lesion (estimated at 30%) located in the left anterior descending coronary artery. Ten days after discharge, the patient suffered another non-ST elevation myocardial infarction. The coronary angiography revealed a surprising sub-occlusive lesion of the left anterior descending coronary artery. Regarding this case, the authors reviewed the literature on the pathophysiology of rapidly progressive coronary artery disease and the approach for non-significant lesions in patients with acute coronary syndrome, especially in the younger population.

Aterectomia rotacional na era dos drug-eluting stents . O ressurgimento duma técnica esquecida?

Although rotational atherectomy (RA) was first introduced in 1986 as a technique for mechanical thrombectomy,1 it was its potential to reduce barotrauma and hence restenosis that sparked the interest of researchers.2--6 Unlike balloon angioplasty, in which acute luminal gain is obtained through stretching of the arterial wall,7--9 RA works by abrading and thereby debulking atherosclerotic plaques.10 The hope was that RA would reduce restenosis by decreasing the quantity of residual plaque after angioplasty, which several intravascular ultrasound studies have shown is one of the most important predictors of restenosis.11 However, it was found that the loss index, a measure of late luminal loss and thus of the efficacy of the technique in terms of restenosis, was no better than with balloon angioplasty.3 In some series in the pre-stent era, RA was associated with restenosis rates as high as 40%, despite apparently reducing barotrauma and the number of dissections.3 Several studies including DART,3 ERBAC,4 STRATAS5 and CARAT,6 as well as meta-analyses,12 did not support the use of RA as a means of reducing restenosis. As a result the technique fell out of favor and is currently employed in less than 5% of procedures in Europe. The widespread use of bare-metal stents, particularly after 1995, led to a new phenomenon, in-stent restenosis. RA was the obvious technique to treat this since it enabled