Continued improvement of clinical outcome and cost effectiveness following intravascular ultrasound guided PCI: insights from a prospective, randomised study.(Interventional Cardiology And Surgery)

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 [euro] in the IVUS guided group versus 313 706 [euro] 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 [euro] 5.2 [euro]; 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.

***********

Intravascular ultrasound (IVUS) offers the unique opportunity of direct inspection of the coronary vessel wall, while angiography shows the lumen only (1-7) In fact, IVUS imaging has shown that angiography underestimates the presence and extent of atherosclerosis. (6 8 9) Moreover, stent underexpansion can frequently be observed with IVUS despite a good angiographic result. (10 11) The use of IVUS during percutaneous coronary intervention (PCI) may therefore help to optimise the results of PCI and particularly of stent implantation. In addition, IVUS provides the operator with more correct information on the real vessel size, which facilitates device selection. (12) The approach of IVUS guided PCI has previously been investigated, generally with a much shorter period of follow up, (13-17) but only a few cost effectiveness analyses on IVUS guidance have been published. (18-21) Most previous studies on IVUS guidance, however, have been performed in high volume centres for PCI.

In the present study, we assessed the major adverse cardiac event (MACE) rate and cost effectiveness of IVUS guidance at five years after inclusion of the first patient in a relatively low volume centre for PCI. A hospital perspective was applied. Our cost effectiveness analysis addressed the cumulative costs related to the initial interventional procedure, hospitalisation, and outpatient treatment. The cost of documentary IVUS in the coronary angiography (CAG) guided group was not included.

METHODS

Study design and inclusion criteria

The study was performed as a prospective randomised clinical trial. Male patients suffering from stable angina pectoris with de novo lesions in native coronary arteries who where scheduled for PCI according to the standard referral system of Odense University Hospital were included. The standard referral criterion for PCI was the visually determined significance of one or two coronary artery lesions by > 50% in symptomatic patients. In case of equivocal significance of the lesion, the patient was first assessed by non-invasive tests according to our hospital routine. This is a widespread clinical approach to PCI referral, in both Europe and the USA, which allows transferring the results of this study to many patients.

Immediately before the procedure, the patients were randomly assigned to PCI guided by IVUS or to angiography only. Randomisation was performed by drawing lots from sealed opaque envelopes. Patients randomised to angiographically guided intervention had so-called "documentary IVUS" before PCI and after completion of the intervention.

The interventional cardiologist was blinded to the results of the IVUS investigation, as the IVUS screen was turned away and the entire pullback remained uncommented on. Nevertheless, all IVUS data were stored and analysed off line to compare the IVUS data of the two groups. Accordingly, we could determine how many patients in both groups achieved the so-called MUSIC (multicenter ultrasound stenting in coronaries) criteria. (22)

Patients randomised to IVUS guided PCI had a pre-PCI IVUS examination. Predilatation with an undersized balloon was performed if the operator was unable to cross the lesion with the IVUS catheter. Device size was chosen based on the information afforded by the IVUS pullback and was optimised until a satisfactory result was obtained or further optimisation seemed to be unsafe. Intracoronary Doppler investigation was carried out before PCI and at completion of the procedure.

Clinical information was obtained by a physician not related to the study. Five years after inclusion of the first patient, patient records were reviewed and the following data were recorded: rehospitalisation rate; length of stay for angina, Q wave acute myocardial infarction (AMI), coronary artery bypass grafting (CABG), death, or target vessel PCI; and the number of outpatient visits in the department of cardiology.

Patient population

The following patients were not considered for this study: firstly, patients with an AMI less than three months before scheduled PCI; secondly, patients who had suffered from unstable angina within a month before the procedure; thirdly, patients with a left bundle branch block; and lastly, patients with atrial fibrillation and those with increased serum creatinine concentration (> 200 [micro] mol/l). Patients in whom PCI proved impossible because of a total occlusion that could not be crossed with a guide wire …