[Photodynamic therapy in cardiac and vascular surgery]. / Terapia fotodinamica in chirurgia cardiaca e vascolare.

One of the major drawbacks to therapeutic cardiovascular intervention is intimal hyperplasia and constrictive remodeling, which result in vascular restenosis. Neointimal hyperplasia is characterized by proliferation and migration of smooth muscle cells. These cells also produce new extracellular matrix, leading to narrowing of vessels. Photodynamic therapy (PDT) represents one of the most promising approaches to the inhibition of intimal hyperplasia. PDT requires the interaction among 3 factors: a source of light, usually a laser, a photosensitizer and oxygen. When the inert photosensitizer absorbs light of a specific wavelength, it is activated to an excited triplet state, generating reactive oxygen species. These free radicals are able to induce apoptosis of the smooth muscle cells that had absorbed the photosensitizer; they also induce changes in the extracellular matrix, reducing cell migration. Because of continued success of PDT in inhibiting intimal hyperplasia in experimental animal models, it is now being tested in clinical trials for vascular diseases. PDT offers many advantages to the surgeon since it can act on numerous factors responsible for vascular lesions. In the future PDT could be used in helping to overcome the inherent failures associated to vascular reconstruction. This treatment modality is emerging as an encouraging therapeutic option, either alone or as an adjunct to conventional treatment. However, more detailed clinical investigation are necessary to determine its full potential.

Papillary muscles and tendinous cords of the right ventricle of the human heart: morphological characteristics.

A series of 79 normal human hearts was studied focusing on the morphological characteristics of the papillary muscles of the right ventricle and their tendinous cords (chordae tendineae). The number, incidence, length and shape of the anterior, septal and posterior papillary muscles were observed. The tendinous cords attached to each papillary muscle were counted at their origin. The papillary muscles and the tendinous cords were measured in situ and after the removal of the right atrioventricular valve (tricuspid valve). The anterior and posterior papillary muscles (apm, ppm) were present in 100% of the cases. The septal papillary muscle (spm) was absent in 21.5% of the hearts. The apm presented 1 head in 81% and 2 heads in 19%; it was 19.16 mm in length. The spm was one-headed in 41.7% and presented two heads in 16.5%; the presence of a 3 and 4 heads appeared in 12.7% and 7.6% respectively; the spm was 5.59 mm in length. The ppm had 1 head in 25.4%, 2 heads in 46.8%, 3 heads in 21.5% and 4 heads in 6.3% of the cases; it was 11.53 mm in length. Tendinous cords (TC) varied as follows: from 1 to 11 TC originated in the apm (mean 4.74); from 1 to 8 TC originated in the ppm (mean 2.67) and from 1 to 5 TC originated in the spm (mean 1.77).

Laser-induced shock waves enhance sterilization of infected vascular prosthetic grafts.

BACKGROUND AND OBJECTIVE: Bacteria that cause infection of vascular prosthetic grafts produce an exopolysaccharide matrix known as biofilm. Growth in biofilms protects the bacteria from leukocytes, antibodies and antimicrobial drugs. Laser-generated shock waves (SW) can disrupt biofilms and increase drug penetration. This study investigates the possibility of increasing antibiotic delivery and sterilization of vascular prosthetic graft. STUDY DESIGN/MATERIALS AND METHODS: Strains of Staphylococcus epidermidis and S. aureus were isolated from infected prosthetic grafts obtained directly from patients. Dacron grafts were inoculated with the isolated bacteria, which were allowed to form adherent bacterial colonies. The colonized grafts underwent the following treatments: (a) antibiotic (vancomycin) alone; (b) antibiotic and SW (c) saline only; and (d) saline and SW. Six hours after treatment, the grafts were sonicated, the effluent was cultured and the colony forming units (CFU) were counted. RESULTS: CFU recovered from control grafts colonized by S. epidermidis were comparable: saline, 3.05 x 10(8) and saline+SW 3.31 x 10(8). The number of S. epidermidis CFU diminished to 7.61 x 10(6) after antibiotic treatment but the combined antibiotic+SW treatment synergistically decreased CFU number to 1.27 x 10(4) (P<0.001). S. aureus showed a higher susceptibility to the antibiotic: 2.26 x 10(6) CFU; antibiotic +SW treatment also had an incremental effect: 8.27 x 10(4) CFU (P<0.001). CONCLUSIONS: This study demonstrates that laser-generated shock waves have no effects alone, but can enhance the effectiveness of antibiotics against bacteria associated with prosthetic vascular graft biofilms, suggesting that this treatment may be of value as adjunctive therapy for prosthetic graft infections.