The histopathology of small vessels following microvascular repair

Abstract

1. The histopathological findings following microvascular repair of 105 arteries and 89 veins in Englishstrain rabbits are reported. 2. The importance of (a) the accurate apposition of the vessel walls and (b) the avoidance of excesive medial necrosis is stressed. 3. The process of subintimal hyperplasia is described and the importance of its role in the repair of small vessels is discussed. Previously, the new formation of elastin tissue has been considered pathognomonic of vascular disease. 4. The appreciably slower rate of repair in veins is also reported. 5. From these observations suggestions have been made with regard to improved technique of surgical repair.

Arterial Repair after Microvascular Anastomosis

“…These changes consist of the necrosis of the media [Acland and Trachtenberg, 1977;Lidmanand Daniel, 1981] and are followed by a prolifera tive inflammatory cellular response described such as subintimal hyperplasia |Baxter et al, 1972: Maxwell et al, 1979 or intimai hyperplasia [Lidman et al, 1984: Morecraft et al, 1988]. An exuberant arterial wall thick ening may cause luminal narrowing at the level of the anastomotic site [Clowes and Reidy, 1987] with conse quent impairment of the blood flow.…”

“…Transmission electron microscopy (TEM) and light microscopy (LM) studies have been also performed [Acland and Trachtenberg. 1977;Baxter et al. 1972;Cuevas andGutierrez.…”

“…This is followed by intimal regenerative phenomena that are usually accompanied by degeneration of the vascular wall with hyperplastic reac tion. Occasionally, vascular occlusion mainly related to thrombus growth occurs [Acland, 1973;Baxter et al, 1972;Morecraft et al, 1988], The application of a careful surgical technique (correct approximation of cut vessel ends, precise apposition of sutures, use of adequate in strumentation, such as stereomicroscope, atraumatic clamps, thin nylon sutures, etc.) seems to be of great importance in shortening the regenerative phase and reducing vascular occlusive complications [Baxter et al, 1972;Derman andSchenk.…”

Microvascular Bypass Grafts

“…3 months postoperatively, the grafts were controlled by angiography and by histopathological examination. We obtained a total patency rate of 52.7°/o and we observed that failure of the grafting can be explained by progres sive hypertrophy of the walls of the vessels inducing thrombosis.The increased accuracy of suture placements provided by microvascu lar techniques now permits direct anastomosis of arteries which measure 0.3 and 1.2 mm in diameter with a permeability patency rate of 91-98#/o [1,3]. This technique is employed specially during cortical cerebral revas cularization proceedings, but it has been limited by increased thrombosis and the impossibility of carrying out direct anastomosis.…”

Sutura mínima associada ao adesivo de fibrina em microanastomoses arteriais: estudo experimental comparativo com a técnica de sutura convencional

“…A lesão da íntima e da camada média, resultantes do número excessivo de pontos e da presença de fios de sutura na luz dos vasos, aumentam o risco de trombose (BAXTER et al, 1972;URBANIAK et al, 1977;WERKER & KON, 1997 Alguns centros utilizaram, experimentalmente, o laser em microanastomoses término-terminais e término-laterais com bons resultados (SARTORIUS et al, 1986;HE et al, 1999). Entretanto, o método exigia treinamento prévio para manipulação do laser, não eliminava totalmente a necessidade de pontos de sutura e o custo do equipamento era elevado.…”