Small-caliber Vessels Research Articles

Anatomical and Technical Tips for Use of the Superficial Inferior Epigastric Artery (SIEA) Flap in Breast Reconstructive Surgery

Techniques for autologous breast reconstruction have evolved to minimize donor-site morbidity and reduce flap-specific complications. When available, the superficial inferior epigastric artery (SIEA) flap represents the optimal method to achieve the former. However, many microsurgeons have been reluctant to adopt this procedure due to technical challenges inherent to the surgery, as well as concerns with the intrinsic capacity of the superficial vessel system to adequately support this flap. This article sets forth a simple approach to the SIEA flap harvest and demonstrates that favorable results may be achieved even for small caliber vessels. A total of 46 patients underwent 53 SIEA breast reconstructions over a 6-year period using a modified approach for pedicle dissection and arterial inclusion criteria solely on the basis of presence of a palpable pulse. Average pedicle length harvested for all SIEA flaps was 6.07 cm; and mean arterial (0.96 mm) and venous (2.27 mm) diameters represent the lowest published values. Three flaps (5.7%) demonstrated fat necrosis or partial flap necrosis, with one (1.9%) complete flap loss. These results compare favorably with those of previous SIEA series employing diameter-based selection criteria, suggesting that the presence of a palpable arterial pulse may be sufficient to permit successful utilization of this flap.

Bioabsorbable device for small‐caliber vessel anastomosis

Although the devices for large-caliber vessel (>2-mm diameter) anastomosis are available, there are no devices for performing anastomosis of small-caliber vessels. We designed a hooked device composed of a bioabsorbable polymer for sutureless anastomosis of small-caliber vessels. The efficacy of this device was evaluated by in vitro degradation and arterial-fixation strength tests as well as in vivo transplantation experiments with common carotid arteries of growing SD rats. A nonabsorbable device without hooks served as the control in the fixation strength and animal experiments. The tensile strength of the bioabsorbable device decreased to 27 and 9% of the initial value after 8- and 24-week incubation, respectively. The fixation strength was greater and the anastomotic time was shorter with this device than with the control. The transplantation experiments showed complete endothelial bridging in both devices at 2 weeks after surgery (n = 6). The control device created a considerable protrusion into the arterial lumen at 8 postoperative weeks, whereas the experimental device did not (n = 6). Arterial diameter measurements detected a significant difference between the inner diameters at the respective anastomotic sites (n = 6, P < 0.05) and demonstrated that the control device hindered the vessel growth while the experimental device did not. Therefore, the bioabsorbable hooked device was an effective tool for anastomosis of small-caliber arteries (ca. 1-mm diameter).

On the Effects of UV‐C and pH on the Mechanical Behavior, Molecular Conformation and Cell Viability of Collagen‐Based Scaffold for Vascular Tissue Engineering

Collagen-based vascular substitutes represent in VTE a valid alternative for the replacement of diseased small-calibre blood vessels. In this study, collagen gel-based scaffolds were crosslinked combining modulation of pH and UV-C radiation. The effects on the mechanical properties, on the molecular structure and on cell viability and morphology were investigated. The mechanical response increased as a function of pH or UV-C dose and strongly depended on the test speed. Collagen molecular conformation resulted only slightly modified. While cell adhesion was not significantly altered, cell proliferation partially decreased in function of pH and UV-C. These findings suggest that UV-C treated collagen gels can represent an adequate substrate for VTE applications.

Dual Energy CT of the Peripheral Arteries: a Phantom Study to Assess the Effect of Automatic Plaque Removal on Stenosis Grading

To evaluate the accuracy of dual energy (DE)-based plaque removal in a vessel phantom. Acrylic vessel phantoms of different diameters (3, 5, 8 mm), degrees of stenoses (25 - 100%) and plaque densities (300 - 750 HU) were filled with contrast-enhanced blood (150 - 450 HU). Dual source CT was used for simultaneous image acquisition at 80 and 140 kV. Beside a DE-based plaque-subtracted dataset (DE-PS), a virtual 120 kV non-plaque subtracted dataset (N-PS) was generated. Agreement between the known and measured luminal diameter in both datasets was determined using Lin's concordance correlation coefficient (kappaLin). A total of 8260 measurements were taken. The correlation of measured diameter in DE-PS images was excellent (kappaLin = 0.83 - 0.96) for 5 - 8 mm vessel phantoms with high luminal enhancement (300 - 450 HU) and plaque density (500 - 750 HU), moderate (kappaLin = 0.6 - 0.67) for 5 mm vessels with lower luminal enhancement and plaque density and poor (kappaLin = 0.10 - 0.64) in the 3 mm vessels. The correlation of N-PS-based stenosis quantification was excellent (kappaLin = 0.86 - 0.99) for 5 - 8 mm vessel phantoms if the contrast between lumen and plaque was above 100 HU. The correlation decreased in 3 mm vessels (kappaLin = 0.45 - 0.93), while the lowest correlation was observed for the lowest contrast between plaque and vessel lumen. Automatic DE-based plaque removal is highly effective for heavily calcified plaques and high luminal enhancement in larger diameter vessels > or = 5 mm). However, accuracy is limited for low density calcified plaque, lower luminal enhancement and smaller caliber vessels mainly due to poor specificity.

Collateral Circulation From the Conus Coronary Artery to the Anterior Descending Coronary Artery: Assessment Using Multislice Coronary Computed Tomography

The prognosis of patients with coronary artery disease largely depends on the presence of a collateral circulation. The location and extent of the collateral circulation is highly variable and these parameters determine whether or not ischemic symptoms occur and whether left ventricular contractility is abnormal. The collateral circulation is generally established through small-caliber distal vessels, although many different forms have been described. We report on three patients with severe left coronary artery disease and collateral circulation through a large conus coronary artery that joined a proximal or medial segment of the left anterior descending coronary artery. In all three cases, left ventricular function was preserved.

Haemangioma of the Parathyroid Gland. Does it Really Exist?

We are reporting a case of a capillary haemangioma-like proliferation arising within a parathyroid gland adenoma, associated with primary hyperparathyroidism. The vessel proliferation bearing a close resemblance to a capillary haemangioma consisted of tightly packed capillaries, endothelial buds and occasional small caliber muscle-containing vessels. The observation expands the spectrum of tumour-associated vascular proliferations by adding an exuberant haemangioma-like pattern to its extreme end. These are a heterogeneous group of lesions reportedly induced by aberrant production of angiogenic factors. We investigated expression of VEGF, pKDR, FGF2, HIF1alpha and HIF2alpha and only VEGF gave a strong positive reaction in the adenoma cells entrapped in the vascular meshwork. Although this does not constitute a proof that aberrant VEGF production was a causative agent, unexpected supportive evidence for its pathogenic role emerged from a failure to detect chromogranin A. Chromogranin A is a precursor of several regulatory proteins, including vasostatin I, a multilevel suppressor of VEGF. The production of vasostatin I may have been reduced in a chromogranin A-negative adenoma which could lead to a loss of its opposing effect on VEGF-regulated processes. The only two other published cases of haemangioma of the parathyroid gland were reported in patients diagnosed with primary parathyroid hyperplasia with hyperparathyroidism, a pathophysiologic condition similar to our case. Therefore we raise the question whether these tumours could also represent a reactive phenomenon.

Evaluating anatomical research in surgery: a prospective comparison of cadaveric and living anatomical studies of the abdominal wall

Cadaveric research has widely influenced our understanding of clinical anatomy. However, while many soft-tissue structures remain quiescent after death, other tissues, such as viscera, undergo structural and functional changes that may influence their use in predicting living anatomy. In particular, our understanding of vascular anatomy has been based upon cadaveric studies, in which vascular tone and flow do not match the living situation. An angiographic analysis of the abdominal wall vasculature was performed using plain film and computed tomography angiography in 60 cadaveric hemi-abdominal walls (from 31 cadavers) and 140 living hemi-abdominal walls (in 70 patients). The deep inferior epigastric artery (DIEA) and all of its perforating branches larger than 0.5 mm were analysed for number, calibre and location. Both large, named vessels and small calibre vessels show marked differences between living anatomy and cadaveric specimens. The DIEA was of larger diameter (4.2 mm versus 3.1 mm, P < 0.01) and had more detectable branches in the cadaveric specimens. Perforators were of greater calibre (diameter 1.5 mm versus 0.8 mm, P < 0.01) and were more plentiful (16 versus 6, P < 0.01) in cadaveric specimens. However, the location of individual vessels was similar. Cadaveric anatomy displays marked differences to in vivo anatomy, with the absence of living vascular dynamics affecting vessel diameters in cadaveric specimens. Blood vessels are of greater measurable calibre in cadaveric specimens than in the living. Consequently, cadaveric anatomy should be interpreted with consideration of post-mortem changes, while living anatomical studies, particularly with the use of imaging technologies, should be embraced in anatomical research.

A new vascular approach to the modified multivisceral graft procurement

Modified multivisceral (MMV) transplantation including the stomach, pancreaticoduodenal complex and intestine requires preservation of the left gastric and splenic arteries. The previously described techniques require division of the hepatic artery proximal to the gastroduodenal artery leaving the liver transplant team with a very short and small caliber vessel. To increase MMV graft availability and provide the liver transplant team with an appropriate quality vessel, we developed the following technique. We also describe two cases where we used this method to support the technical feasibility of this procedure.

Patent Blue Dye in Lymphaticovenular Anastomosis

Lymphaticovenular anastomosis (LVA) has been described as a treatment of chronic lymphoedema. This microsurgical technique is new and technically difficult. The small caliber and thin wall lymphatic vessels are difficult to identify and easily destroyed during the dissection. We describe a technique of performing lymphaticovenular anastomosis with patent blue dye enhancement. Our patient is a 50-year-old lady who suffers from chronic lymphoedema of the upper limb after mastectomy and axillary clearance for breast cancer 8 years ago. Patent blue dye is injected subdermally and is taken up readily by the draining lymphatic channels. This allows for easy identification of their course. The visualisation of the lumen of the lymphatic vessel facilitates microsurgical anastomosis. The patency of the anastomosis is also demonstrated by the dynamic pumping action of the lymphatic within the vessels. Patent blue dye staining during lymphaticovenular anastomosis is a simple, effective and safe method for mapping suitable subdermal lymphatics, allowing for speedier dissection of the lymphatic vessels intraoperatively. This technique also helps in the confirmation of the success of the lymphaticovenular anastomosis.

The effect of exercise on the cerebral vasculature of healthy aged subjects as visualized by MR angiography.

Prior studies suggest that aerobic exercise may reduce both the brain atrophy and the decline in fractional anisotropy observed with advancing age. It is reasonable to hypothesize that exercise-induced changes to the vasculature may underlie these anatomic differences. The purpose of this blinded study was to compare high-activity and low-activity healthy elderly volunteers for differences in the cerebrovasculature as calculated from vessels extracted from noninvasive MR angiograms (MRAs). Fourteen healthy elderly subjects underwent MRA. Seven subjects reported a high level of aerobic activity (64 +/- 5 years of age; 5 men, 2 women) and 7, a low activity level (68 +/- 6 years of age; 5 women, 2 men). Following vessel segmentation from MRA by an individual blinded to subject activity level, quantitative measures of vessel number, radius, and tortuosity were calculated and histogram analysis of vessel number and radius was performed. Aerobically active subjects exhibited statistically significant reductions in vessel tortuosity and an increased number of small vessels compared with less active subjects. Aerobic activity in elderly subjects is associated with lower vessel tortuosity values and an increase in the number of small-caliber vessels. It is possible that an aerobic exercise program may contribute to healthy brain aging. MRA offers a noninvasive approach to visualizing the cerebral vasculature and may prove useful in future longitudinal investigations.

Scanning electron microscopy study of bone intracortical vessels using an injection and fractured surfaces technique

The intracortical canal/vessel systems of long bones are not yet completely understood in terms of their morphology and physiology, mainly because of the difficulty of injecting the small calibre vessels and cutting the calcified matrix. Here, we apply a novel method combining perfusion of the vessels and fracture of the cortical bone to enlighten the architecture of this system. The femurs of ten rabbits were perfused with a water-soluble dye (China ink) or alcoholic glycerol solution, and the fractured cortex specimens were then examined by scanning electron microscopy (SEM). The results document: (1) the fibrillar structure of the canal surfaces; (2) the perivascular environment with cellular components in different phases of incorporation within the bone matrix; (3) previously unreported filamentous structures on the outer surface of vessels, which could be interpreted as non-myelinic nerve fibres; (4) the inner organisation of the cutting cones. Although based exclusively on morphology, these observation have some relevance to increasing knowledge of bone circulation physiology in the cortical bone.

Metastatic Angioinvasive Lymphoma (Lymphomatoid Granulomatosis) in a Cat

A subcutaneous mass removed from the right rear leg of a 17-year-old, spayed, female Domestic Shorthair cat was characterized histopathologically by granulomatous inflammation, sheets of large atypical lymphoid cells, and necrosis. The walls of the small and medium caliber blood vessels were invaded transmurally by atypical lymphoid cells. A diagnosis of angioinvasive lymphoma (AIL), or lymphomatoid granulomatosis, was made based on histopathologic findings. The cat was euthanized 2 months later because of recurrence of the mass and elevated serum alanine aminotransferase activity, and a necropsy was performed. The histopathologic lesion of AIL was seen in the skin and subcutis of the right rear leg, and neoplastic cell infiltrates were seen in adjacent skeletal muscle, right superficial inguinal lymph node, liver, and spleen. By immunohistochemistry, variable numbers of neoplastic cells expressed B-lymphocyte antigen 36 (BLA36) or cluster of differentiation (CD)3 markers, indicative of B- and T-cell lineages, respectively. Neoplastic cells were uniformly positive for vimentin and uniformly negative for cytokeratins and myeloid/histiocytic antigen. Although the cat had received a Rabies virus vaccine subcutaneously in the right rear leg 6 months earlier, the AIL lesion was not typical of vaccine-induced sarcomas. The AIL in this cat was unusual because the extrapulmonary metastases involved the skin and subcutis.

PR32P EVALUATING ANATOMICAL RESEARCH IN SURGERY: A PROSPECTIVE COMPARISON OF CADAVERIC AND LIVING ANATOMICAL STUDIES OF THE ABDOMINAL WALL

Background: Cadaveric research has widely influenced our understanding of clinical anatomy. However, while many soft‐tissue structures remain quiescent after death, other tissues undergo structural and functional changes that may influence their use in predicting living anatomy. In particular, our understanding of vascular anatomy has been based upon cadaveric studies in which vascular tone and flow do not match the living situation.Methods: An angiographic analysis of the abdominal wall vasculature was performed using plain‐film and computed tomography (CT) angiography in 60 cadaveric and 140 living (70 patients) hemi‐abdominal walls The deep inferior epigastric artery (DIEA) and all of its perforating branches larger than 0.5 mm were analysed for number, calibre and location.Results: Both large, named vessels and small calibre vessels show marked differences between living anatomy and cadaveric specimens. The DIEA was of larger diameter (4.2 mm vs. 3.1 mm, p &lt; 0.01) and had more detectable branches in the cadaveric specimens. Perforators were of greater calibre (diameter 1.5 mm vs. 0.8 mm, p &lt; 0.01) and were more plentiful (16 vs. 6, p &lt; 0.01) in cadaveric specimens. However, the location of individual vessels was similar.Conclusions: Cadaveric anatomy displays marked differences to in‐vivo anatomy, with the absence of living vascular dynamics affecting vessel diameters in cadaveric specimens. Blood vessels are of greater measurable calibre in cadaveric specimens than in the living. Consequently, cadaveric anatomy should be interpreted with consideration of post‐mortem changes, while living anatomical studies, particularly with the use of imaging technologies, should be embraced in anatomical research.

Pseudotumor pulmonar como apresentação inicial de granulomatose de Wegener

Wegener's granulomatosis is a multisystemic inflammatory illness of unknown etiology, characterized by vasculitis of small and medium caliber vessels. The most common clinical manifestations involve the upper respiratory tract, lungs and kidneys. Common alterations in imaging studies include pulmonary opacities and bilateral multiple nodules, cavitations occurring in 50% of the cases. Treatment includes corticosteroids and immunosuppressants. We describe an atypical case of a 61-year-old man initially investigated due to suspicion of a unilateral lung tumor, which proved to be, in fact, a case of Wegener's granulomatosis.

Infantile fibrosarcoma: Clinical and histologic responses to cytotoxic chemotherapy

Infantile fibrosarcoma (IF) is a rare soft tissue sarcoma that presents either at birth or in the first year of life. Complete surgical resection is usually curative but chemotherapy may shrink the tumor to facilitate complete resection. This report describes the histologic changes and outcomes in four patients with IF treated with chemotherapy and surgical resection. A retrospective review was performed of patients treated between 2000 and 2007. All four patients are alive with excellent functional outcomes. The patients were diagnosed from birth up to 7 months of age; three had lower extremity tumors and one had a neck tumor. All patients received vincristine, cyclophosphamide, and actinomycin; one patient also received ifosfamide and etoposide after tumor progression. One tumor, arising from the neck, had rapid shrinkage. Two lower extremity tumors had only modest changes in dimensions but upon resection, the tumor bed contained fibrous tissue with exaggerated small caliber vessels. The fourth infant developed metastatic lesions in the central nervous system, orbits, lungs, and kidney after complete removal of the primary tumor. The metastatic lesions responded to chemotherapy and have remained stable for over 3 years. IF is a chemosensitive tumor. In patients where a clinical response is not apparent, cytoreduction of the tumor and replacement with fibrotic and fibrovascular tissue may facilitate gross-total resection. The chemotherapy-responsiveness of this tumor may abrogate unfavorable features such as metastatic or residual tumor.

Successful Treatment of Six Cases of Indirect Carotid-Cavernous Fistula with Ethylene Vinyl Alcohol Copolymer (Onyx) Transvenous Embolization

Endovascular transvenous treatments have become the mainstay in the management of indirect carotid-cavernous fistulas (CCFs). However, the standard coil techniques are associated with a substantial failure and complication rate. The ethylene vinyl alcohol copolymer (Onyx) Liquid Embolization System has advantages over coils, including the ability to penetrate and occlude vessels of small caliber or with difficult access. This was a review of 5 consecutive patients with indirect type D CCFs who underwent 6 procedures using the Onyx system alone at the Prince of Wales Hospital, Sydney, between December 2005 and May 2007. The cavernous sinus was catheterized with MTI Echelon-10 or Rebar-14 microcatheters via the femoral vein using an inferior petrosal approach to the cavernous sinus in 5 procedures and directly via the superior ophthalmic vein in 1 procedure. All 5 patients had complete closure of the fistulas as seen on imaging and full reversal of ophthalmic manifestations without lingering complications and with substantially shorter procedure times than with conventional approaches. The Onyx system is a safe and useful method of closing indirect CCFs transvenously. This is the first series report of the use of the Onyx system alone in the treatment of these vascular abnormalities.

Developing Lifeline™, a Small-Caliber Autologous Tissue-Engineered Blood Vessel, for Clinical Trials in Germany

Developing Lifeline™, a Small-Caliber Autologous Tissue-Engineered Blood Vessel, for Clinical Trials in Germany

Time dependent vascular and myocardial responses of a second generation, small vessel, paclitaxel‐eluting stent platform

The purpose of this study was to evaluate the time-dependent vascular and myocardial responses to a second-generation, small vessel (< or =2.5 mm) paclitaxel-eluting stent (PES) platform. Small caliber coronary vessels present complex challenges for percutaneous coronary intervention (PCI) and are associated with lower technical success and inferior long-term efficacy. A next-generation, highly deliverable PES may improve clinical outcomes in small vessels. Sixty single stents were implanted in noninjured coronary arteries in 30 domestic swine (one TAXUS Liberté small vessel PES (svPES) and one Liberté small vessel bare metal stent (svBMS) in each animal). Ten animals each were allocated to 30-, 90-, and 180-day follow-up groups; final quantitative angiography and necropsy were performed. Samples of myocardium, liver, and kidney were processed and evaluated for pathology. Radiography and either histopathology or scanning electron microscopy were performed on all the explanted stented vessels. There were no stent-related deaths or downstream myocardial pathology. Both the svPES stent and its svBMS control demonstrated complete strut tissue coverage and complete endothelialization at all timepoints, and there was no evidence of macro- or microscopic thrombus or stent fracture. Medial smooth muscle cell content was markedly reduced in all the svPES groups compared with that in the svBMS controls. The small diameter paclitaxel-eluting TAXUS Liberté stent has a safe and predictable biologic vascular response in the noninjured swine model. This device warrants further investigation targeting the currently poorly met clinical need for small vessel PCI.

Sirolimus-eluting stent implantation in small coronary arteries: A three dimensional intravascular ultrasound study from the SIRIUS trial

Aim To assess the efficacy of the sirolimus-eluting stent when implanted in smaller caliber vessels using three-dimensional intravascular ultrasound (IVUS) analysis. Methods One hundred and twenty-three patients (69 sirolimus-coated Bx Velocity and 54 control) who underwent successful three-dimensional IVUS at follow up comprised this IVUS substudy from the SIRIUS (SIRolImUS-coated Bx Velocity stent in the treatment of patients with de novo coronary artery lesions) population. To evaluate the impact of vessel size, 2 groups were created using QCA reference vessel diameter (RVD; large vessel group: RVD ≥ 2.75 mm and small vessel group: RVD < 2.75 mm). Results Sirolimus-eluting stents significantly reduced neointimal hyperplasia by the same relative magnitude within the stent in small vessels as well as in large vessels. Although sirolimus-eluting stents had favorable effects on lumen area at stent edges in larger vessels, the effect was less in smaller vessels, especially at the proximal edge. IVUS-detected adverse vessel response, such as late-acquired incomplete apposition, did not increase in smaller vessels even with relatively higher dose exposure. Conclusion Sirolimus-eluting stents showed inhibition of neointimal hyperplasia in small vessels compared to bare metal stents with no increase of vascular complications.

Stem cells used for cardiovascular tissue engineering☆

Stem cell research and tissue engineering have become leading fields in basic research worldwide. Especially in cardiovascular medicine, initial reports on the potential of using stem cells to recover cardiac function and replace organ subunits such as heart valves seemed to offer the promise of widespread clinical use in the near future. However, the broad application of this new therapy failed due to safety and efficacy concerns. Due in part to the initial reports, major basic research efforts were undertaken to explore the specific cell types in greater detail and identify their mechanisms of supporting function, resulting in remarkable new findings in stem cell biology. For example, the notion of resident human cardiac stem cells has disproved the earlier supposition that the human heart is a finitely differentiated organ without the intrinsic potential for regeneration. Furthermore, new technologies emerged to produce pluripotent cells without the ethical and immunological drawbacks of embryonic stem cells (for instance by nuclear transfer). Other autologous cell sources are presently under investigation in myocardial tissue engineering. For tissue engineering of heart valves and small calibre vessels, the use of autologous endothelial (precursor) cells may be the optimal means of seeding a biological or artificial scaffold. It is important that ongoing basic and clinical research in cardiovascular surgery might explore the potential of different cell types either using tissue engineering constructs or in cell transplantation approaches.