Acute and mid-term outcomes after treatment of multiple, recurrent restenoses of the lower limb arteries.

AIM: Recanalization of long segmental occlusions of femoropopliteal arteries can be achieved by angioplasty and implantation of nitinol stents with high procedural success rates. However, due to recurrent in-stent restenoses (ISR) some patients need repeated interventions and their intermediate success rates are uncertain. METHODS: Patients who were treated in our center from March 2008 through February 2011 due to symptomatic ISR (as determined by Duplex sonography) were retrospectively included in the study. After endovascular treatment of their ISR, they were prospectively evaluated with regard to recurrent ISR of the target lesions. RESULTS: A total of 36 limbs (=lesions) in 32 patients (69% male, mean age 69±9 years) were successfully treated by balloon-angioplasty. Adjunctive cutting balloons and drug eluting balloons were used in 78% and 8%, respectively. Mean follow-up was 326 days. Recurrent ISR occurred in 10 (28%) lesions, while 26 (78%) lesions showed no recurrence of ISR. In a multivariate logistic regression analysis, age, gender, cardiovascular risk factors, renal failure and medication with cilostazol were not significantly associated with recurrent ISR. Moreover, the number of previous interventions of the target lesions was not an independent predictor of recurrent ISR. CONCLUSION: Patients with multiple recurrences of ISR seem to have the same prospects of acute and mid-term success for endovascular treatment as those with first presentation of ISR. However, this observation has to be confirmed by prospective, large scale studies with a longer follow-up period to determine the significance of endovascular intervention within the scope of different revascularization approaches for treatment of recurrent ISR.

Impact of coronary vasa vasorum functional structure on coronary vessel wall perfusion distribution.

Noncoronary vasa vasorum have been described as networks of microvessels in the wall of arteries and veins. However, we have shown, using microcomputerized tomography (micro-CT) imaging methods, that porcine coronary vasa vasorum have a tree-like branching structure similar to the vasculature in general. In this study, we elucidate functional aspects of coronary vasa vasorum perfusion territories. Three pig hearts were injected with radiopaque Microfil via the coronary sinus to fill the left anterior descending coronary arteries (LADs) retrogradely at atmospheric pressure. In three other hearts, LADs were injected antegradely at 100-mmHg pressure via the left main carotid artery. Additionally, six LADs were injected in vivo with a suspension of 100- or 300-microm-diameter microspheres before harvesting of the hearts and injection of the LADs with Microfil. All harvested LADs were scanned intact with micro-CT (20 microm cubic voxels). The spatial density of vasa vasorum (no. of vasa/mm2) was measured in 20-microm-thick cross sections (at 0.4-mm intervals). Retrogradely injected LADs showed high and uniformly distributed vasa vasorum densities in the adventitia (means +/- SE; 5.38 +/- 0.09 vs. 3.58 +/- 0.1 vasa/mm2 in antegradely prepared LADs; P < 0.001). Antegradely prepared LADs showed patchy distributed, low-vasa-vasorum-density territories especially on the myocardial side of the coronary artery wall (epicardial density: 4.29 +/- 0.13 vasa/mm2 vs. myocardial density: 2.80 +/- 0.1 vasa/mm2, P < 0.001). Microembolization reduced vasa vasorum densities significantly (100-mum-diameter microspheres: 3.26 +/- 0.07 vasa/mm2, P < 0.05; 300-microm-diameter microspheres: 2.66 +/- 0.07 vasa/mm2, P < 0.001 vs. antegrade controls) and increased the size of low-vasa-vasorum-density territories. We conclude that coronary vasa vasorum are functional endarteries not connected via a plexus. This characteristic may have a significant impact on the spatial distribution of perfusion and drainage of the coronary vessel wall.