Continued improvement of clinical outcome and cost effectiveness following intravascular ultrasound guided PCI: insights from a prospective, randomised study

OBJECTIVE

To investigate in a prospective randomised study both long term clinical effects and cost effectiveness of percutaneous coronary interventions (PCI) with or without intravascular ultrasound (IVUS) guidance.

METHODS

108 male patients with stable angina referred for PCI of a significant coronary lesion were randomly assigned to IVUS guided PCI or conventional PCI. Individual accumulated costs of the entire follow up period were calculated and compared in the randomisation groups. Effectiveness of treatment was measured by freedom from major adverse cardiac events.

RESULTS

Cost effectiveness of IVUS guided PCI that was noted at six months was maintained and even accentuated at long term follow up (median 2.5 years). The cumulated cost level was found to be lower for the IVUS guided group, with a cumulated cost of &163 672 in the IVUS guided group versus &313 706 in the coronary angiography group (p = 0.01). Throughout the study, mean cost per day was lower in the IVUS guided PCI group (&2.7 v & 5.2; p = 0.01). In the IVUS group, 78% were free from major adverse cardiac events versus 59% in the coronary angiography group (p = 0.04) with an odds ratio of 2.5 in favour of IVUS guidance.

CONCLUSION

IVUS guidance results in continued improvement of long term clinical outcome and cost effectiveness. The results of this study suggest that IVUS guidance may be used more liberally in PCI.

Reproducibility of intravascular ultrasound and intracoronary Doppler measurements

The aim of this study was to evaluate the reproducibility of intravascular ultrasound (IVUS) and intracoronary (IC) Doppler flow velocity measurements. The use of IVUS and IC Doppler has been suggested as a means for percutaneous coronary intervention (PCI) guidance in a series of studies. This would require an acceptable level of accuracy and reproducibility of these two methods for lesion evaluation. In this study, the main focus was on the issue of reproducibility. One hundred and eight patients referred for PCI entered into the study. Inter- and intraobserver variability was measured. Catheter difference was assessed. On-line and off-line measurements were compared. MUSIC criteria were assessed off-line, twice. Calculated and measured diameters were compared. After having obtained initial IC Doppler measurements, the Doppler wire was immediately withdrawn and repositioned for reacquisition of Doppler measurements. IVUS measurements are reproducible and reliable off-line and, to a slightly lesser degree, on-line. Area measurements should be performed more than once and the mean used for vessel description. Lumen diameters should be calculated from the mean of the area measurements. A measuring technique consensus should be reached and adhered to. CFR measurements can be used to determine reduced vs. normal flow reserve. In this study, it was found that proximal to distal velocity ratio and diastolic to systolic velocity ratio variability made these parameters unsuitable for PCI guidance.

Myocardial perfusion imaging and coronary angiography in patients with known or suspected stable angina pectoris

INTRODUCTION

The patho-physiological cause of angina pectoris is myocardial ischaemia, which can be objectified by myocardial perfusion imaging (MPI).

METHODOLOGY

MPI was undertaken prior to coronary angiography (CAG) in 86 randomly selected patients with known or suspected stable angina pectoris.

RESULTS

Among 78 adequately stressed patients, MPI was normal in 28 (36%) and showed reversible and irreversible perfusion abnormalities in 30 (38%) and 20 patients (26%), respectively. Coronary angiograms were normal in 28 (36%) and revealed at least one > or = 50% stenosis in 50 patients (64%) (16 with single and 34 with multi vessel disease). Using angiography as a reference, the sensitivity and specificity of MPI in detecting coronary artery disease was 88% and 93%, respectively.

DISCUSSION

MPI demonstrates regional hypoperfusion whereas CAG depicts anatomical stenosis in epicardial arteries. Both modalities are potentially relevant in patients with stable angina pectoris. The functional significance of coronary artery lesions is, however, variable and MPI can demonstrate normal myocardial perfusion in the presence of moderate lesions. MPI exhibited a high sensitivity and specificity regarding significant lesions. More than one third of the subjects had a normal MPI and a normal CAG. Patients with stable angina pectoris and a normal MPI have a very low risk of cardiac events and do usually not require further invasive investigation or therapy. Reversible ischaemia and irreversible ischaemia with demonstration of viable tissue call for coronary revascularisation.

Interpretive intra- and interobserver reproducibility of rest/stress 99Tcm-sestamibi myocardial perfusion SPECT in a consecutive group of male patients with stable angina pectoris before and after percutaneous transluminal angioplasty

BACKGROUND

Observer variability of 99Tcm-sestamibi myocardial perfusion imaging (MPI) has rarely been investigated. The aim of our study was to evaluate the interpretive reproducibility with this technique.

PATIENTS

We report on 108 consecutive male patients with stable angina pectoris, investigated before and after percutaneous transluminal angioplasty (PTCA).

METHODS

A 2-day rest/stress 99Tcm-sestamibi gated single photon emission computed tomography (SPECT) protocol was used. MPI was interpreted by two independent observers without knowledge of clinical data, using a 20-segment scoring model.

RESULTS

Intra- and interobserver agreement was found to be good to excellent (kappa = 0.71-0.85) with regard to the overall diagnosis as well as the individual vessel diagnosis (kappa = 0.60-0.87). However, agreement was higher for left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCX) vascular territories than for the right coronary artery (RCA) territory. Moderate to good intraobserver agreement (kappa = 00.54-0.68) and slightly lower interobserver agreement (kappa = 0.52-0.56) was found for segmental score interpretation. When comparing the interpretive reproducibility before and after PTCA intra- and interobserver agreement was better after PTCA, probably reflecting the increase in normal scans after revascularization.

CONCLUSIONS

In a group of consecutive male patients with stable angina pectoris interpretive reproducibility (overall and individual vessel diagnosis) was good to excellent. However, segmental scoring reproducibility was moderate to good.

[Myocardial scintigraphy and coronary arteriography in patients with known or suspected stable angina pectoris]

INTRODUCTION

Myocardial perfusion imaging (MPI) demonstrates regional hypoperfusion, whereas coronary angiography shows anatomical stenoses in epicardial arteries. Both modalities are potentially relevant in patients with stable angina pectoris.

MATERIALS AND METHODS

MPI was undertaken before angiography in 86 randomly selected patients with stable angina pectoris.

RESULTS

Of 78 adequately stressed patients, MPI was normal in 28 (36%) and showed reversible and irreversible perfusion abnormalities in 30 (38%) and 20 patients (26%), respectively. Coronary angiograms were normal in 28 (36%) and revealed at least one > or = 50% stenosis in 50 patients (64%) (16 with single vessel and 34 with multivessel disease). With angiography as reference, the sensitivity and specificity of MPI in the detection of coronary artery disease were 88% and 93%, respectively.

DISCUSSION

Patients with stable angina pectoris and a normal MPI have a very low risk of cardiac events and do not usually require invasive investigation and therapy. Reversible ischaemia and irreversible ischaemia with viable tissue call for coronary revascularisation.

Cost-effectiveness analysis of intravascular ultrasound guided percutaneous coronary intervention versus conventional percutaneous coronary intervention

OBJECTIVE

Investigation of the cost-effectiveness of intravascular ultrasound (IVUS) guided percutaneous coronary intervention (PCI) compared to PCI guided by coronary angiography (CAG).

METHODS

One hundred and eight men referred for PCI, were randomized to IVUS or CAG guided PCI. After 6 months, the patients were subjected to a study related clinical and invasive follow-up investigation by CAG, IVUS and intracoronary Doppler flow measurements. Incremental costs of IVUS guided procedures and costs of re-interventions were estimated using the Activity Based Costing (ABC) method.

RESULTS

Patients randomized to IVUS guided PCI experienced an improved clinical outcome, with lower angina levels than patients in the CAG guided group. The initial cost of performing IVUS guidance was increased due to extra procedure time, IVUS catheters and slightly more balloons and stents, but fewer patients in the IVUS guided group needed re-intervention. Overall, these savings outweighed the initial cost increase.

CONCLUSION

Our data suggest that when performing IVUS guided PCI, costs as well as benefits increase. The increased benefits measured as cost savings resulting from less restenosis outweigh the cost increase from performing the IVUS guided PCI as opposed to CAG guided PCI.

Three dimensional intravascular ultrasonic assessment of the local mechanism of restenosis after balloon angioplasty

OBJECTIVE

To assess the mechanism of restenosis after balloon angioplasty.

DESIGN

Prospective study.

PATIENTS

13 patients treated with balloon angioplasty.

INTERVENTIONS

111 coronary subsegments (2 mm each) were analysed after balloon angioplasty and at a six month follow up using three dimensional intravascular ultrasound (IVUS).

MAIN OUTCOME MEASURES

Qualitative and quantitative IVUS analysis. Total vessel (external elastic membrane), plaque, and lumen volume were measured in each 2 mm subsegment. Delta values were calculated (follow up - postprocedure). Remodelling was defined as any (positive or negative) change in total vessel volume.

RESULTS

Positive remodelling was observed in 52 subsegments while negative remodelling occurred in 44. Remodelling, plaque type, and dissection were heterogeneously distributed along the coronary segments. Plaque composition was not associated with changes in IVUS indices, whereas dissected subsegments had a greater increase in total vessel volume than those without dissection (1.7 mm(3) v -0.33 mm(3), p = 0.04). Change in total vessel volume was correlated with changes in lumen (p < 0.05, r = 0.56) and plaque volumes (p < 0.05, r = 0.64). The site with maximum lumen loss was not the same site as the minimum lumen area at follow up in the majority (n = 10) of the vessels. In the multivariate model, residual plaque burden had an influence on negative remodelling (p = 0.001, 95% confidence interval (CI) -0.391 to -0.108), whereas dissection had an effect on total vessel increase (p = 0.002, 95% CI 1.168 to 4.969).

CONCLUSIONS

The mechanism of lumen renarrowing after balloon angioplasty appears to be determined by unfavourable remodelling. However, different patterns of remodelling may occur in individual injured coronary segments, which highlights the complexity and influence of local factors in the restenotic process.

[Prognosis after primary acute myocardial infarction]

Results from many clinical trials have changed treatment strategies, but due to considerable selection caused by extensive inclusion- and exclusion criteria the results are only valid for smaller groups, while the majority of the patients still suffer from high mortality with conservative treatment. We have during eight years followed 933 patients with first myocardial infarction and found that the group who tolerated treatment with thrombolytic agents had a lower mortality than the rest. On the other hand, infarct patients are generally old, often with concomitant chronic diseases which affect mortality, and this in combination with heart-failure and cardiac arrhythmias determines outcome. Better prophylactic and treatment measures are needed to improve survival of ischaemic heart disease.

Intravascular ultrasound in equivocal coronary angiography

Intravascular ultrasound (IVUS) is a well-established diagnostic tool that supplements coronary angiography in the evaluation of angiographical intermediate lesions as well as guiding Percutaneous transluminal coronary angioplasty. In this case report we describe the benefit of IVUS in diagnosing pseudostenosis as opposed to angiographically suspected guidewire induced dissection, and suggest the use of IVUS in all cases where angiography is equivocal. We also report a case of preoperative IVUS where the IVUS finding resulted in further coronary artery bypass grafting and suggest IVUS as a feasible alternative to probing of coronary arteries suspected of stenosis during coronary artery bypass grafting.

[Evaluation of functional importance of coronary artery stenosis by intracoronary Doppler blood flow velocity measurement]

Intracoronary doppler blood flow velocity measurements supply important information for clinical decision making during angioplasty, especially with regard to stenoses of ambiguous severity. In the presence of an intermediate stenosis of unknown physiological impact (40-60%), determination of normal flow parameters (coronary flow reserve: CFR, diastolic to systolic velocity ratio: DSVR and proximal to distal velocity ratio: P/D) will make deferment of treatment acceptable. Post-angioplasty success can be based on restoral of normal flowparameters. The inability to achieve normal CFR immediately after angioplasty does not indicate an unsuccessful procedure, it remains to be shown whether a lack of normalization of DSVR and/or P/D does so. Continuous post-lesional flow monitoring can show and quantify the existence of collateral flow.