Ischemia and reperfusion injury in superficial inferior epigastric artery-based vascularized lymph node flaps.

Vascularized lymph node transfer (VLNT) is a promising treatment modality for lymphedema; however, how lymphatic tissue responds to ischemia has not been well defined. This study investigates the cellular changes that occur in lymph nodes in response to ischemia and reperfusion. Lymph node containing superficial epigastric artery-based groin flaps were isolated in Prox-1 EGFP rats which permits real time identification of lymphatic tissue by green fluorescence during flap dissection. Flaps were subjected to ischemia for either 1, 2, 4, or 8 hours, by temporarily occluding the vascular pedicle. Flaps were harvested after 0 hours, 24 hours, or 5 days of reperfusion. Using EGFP signal guidance, lymph nodes were isolated from the flaps and tissue morphology, cell apoptosis, and inflammatory cytokines were quantified and analyzed via histology, immunostaining, and rtPCR. There was a significant increase in collagen deposition and tissue fibrosis in lymph nodes after 4 and 8 hours of ischemia compared to 1 and 2 hours, as assessed by picrosirius red staining. Cell apoptosis significantly increased after 4 hours of ischemia in all harvest times. In tissue subject to 4 hours of ischemia, longer reperfusion periods were associated with increased rates of CD3+ and CD45+ cell apoptosis. rtPCR analysis demonstrated significantly increased expression of CXCL1/GRO-α with 2 hours of ischemia and increased PECAM-1 and TNF-α expression with 1 hour of ischemia. Significant cell death and changes in tissue morphology do not occur until after 4 hours of ischemia; however, analysis of inflammatory biomarkers suggests that ischemia reperfusion injury can occur with as little as 2 hours of ischemia.

Vía de parto en gestante portadora de prótesis de aorta abdominal: caso clínico / Way of delivery in pregnant carrier of abdominal aortic prosthesis

Se presenta el caso de una gestante de 34 años portadora by-pass aorto-aórtico con prótesis de Dacron(R) por antecedente de rotura iatrogénica de la aorta abdominal durante una colecistectomía laparoscópica. Ante la falta de evidencia científica sobre gestantes portadoras de prótesis aórticas abdominales y vía de finalización del parto, se lleva el caso a comité, formado por un equipo multidisciplinar que incluye cirujanos vasculares, anestesistas y obstetras y se decide finalmente programar cesárea en la semana 39. Revisando los cambios hemodinámicos producidos no solo durante la gestación sino durante el trabajo de parto se ha visto que estos pueden influir negativamente en el injerto de Dacron de nuestra paciente, conllevando un riesgo importante sobre la misma y el feto. Por todo ello consideramos correcta la decisión tomada por el comité de indicar una cesárea como vía de finalización de la gestación

We present the case of a 34-years-old, pregnant patient, aorto-aortic by-pass carrier with a Dacron(R) prosthesis due to a history of iatrogenic rupture of the abdominal aorta during a laparoscopic cholecystectomy. Due to the lack of scientific evidence on pregnant carriers of abdominal aortic prostheses and type of delivery, the case is taken to committee, formed by a multidisciplinary team including vascular surgeons, anesthetists and obstetricians and finally decided to schedule cesarean section at 39 weeks. Reviewing hemodynamic changes produced during pregnancy and labor has been seen that these can negatively influence the Dacron(R) graft of our patient, leading to a significant risk to the pregnant and the fetus. For all these reasons, we consider correct the decision taken by the committee to indicate a cesarean section as a way of delivery

Acute gastric volvulus / Vólvulo gástrico agudo

No disponible

Vasopressor support vs. liberal fluid administration in deep inferior epigastric perforator (DIEP) free flap breast reconstruction - a randomized controlled trial.

BACKGROUND: Perioperatively, patients' hemodynamics are modulated predominantly by intravenous fluid administration and vasoactive pharmacological support. Vasopressor agents are suspected to be detrimental on free flap survival by the cause of vasoconstriction of the pedicle with consecutive reduced overall flap perfusion and by aggravation of flap dissection. OBJECTIVE: A novel, standardized fluid restrictive perioperative hemodynamic management was assessed for its feasibility in clinical practice in free flap patients undergoing breast reconstruction. METHODS: Patients were randomized to two perioperative regimens with different fluid and vasopressor limits. The primary endpoint regarded flap survival. Secondary endpoints included surgery times, time of patient ambulation and length of hospital stay. RESULTS: There was one total flap failure with liberal fluid administration (LFA). No total or partial flap failure was noted in the fluid restrictive regimen with norepinephrine administration up to 0.04µg/kg/min (FRV). No delay regarding operation time (p = 0.217), patient mobilization (p = 0.550) or hospital discharge (p = 0.662) was registered in the FRV study subpopulation compared to LFA. CONCLUSIONS: The results of this prospective interventional trial could not detect any negative impact of vasopressors, neither for the primary endpoint of flap survival nor for the overall patient outcome. The fear of vasopressor associated flap complications has led to a traditional liberal fluid administration, which failed to demonstrate any benefits when compared to a fluid restrictive vasopressor strategy.

Algorithmic Approach for Intraoperative Salvage of Venous Congestion in DIEP Flaps.

BACKGROUND: Flap congestion is a frequently described intraoperative complication during autologous breast reconstruction with abdominal perforator flaps, which, if not addressed, can lead to detrimental results such as flap failure. Here, we describe our institution's algorithm of intraoperative salvage of congested flaps and present their outcomes. PATIENTS AND METHODS: All patient charts from 2002 to 2016 of a single plastic surgeon were reviewed for patients who underwent deep inferior epigastric perforator flap breast reconstruction resulting in 602 patients and 831 flaps. Of those, 38 women (6.3%) with 40 congested flaps (4.8%) were included in this study. Based on the algorithm guiding the selection of additional venous anastomosis, the patients' surgical details, outcomes, as well as their demographic characteristics are evaluated. RESULTS: Average age and body mass index of our cohort were 47.0 ± 8.0 years and 26.1 ± 3.9, respectively. Ten patients (26.3%) were current or former smokers while 20 (52.6%) required external radiation. Thirty-two congested flaps (80.0%) were predominantly salvaged with a superficial inferior epigastric vein (SIEV)-to-deep inferior epigastric vein (comitante) anastomosis. An SIEV-to-internal mammary vein comitante anastomosis was the second favorite option (5 flaps, 12.5%). Five patients suffered minor complications within a mean follow-up of 18.8 ± 12.3 months without flap failure, bleeding, or infection. CONCLUSIONS: Venous flap congestion is an uncommon intraoperative intricacy during free tissue transfer for autologous breast reconstruction. Our proposed algorithm primarily recommends adding an additional venous anastomosis between the superficial and deep drainage system and results and favorable outcomes without major complications.

Current Practices in the Management of Postoperative Arterial Vasospasm in Microsurgery.

BACKGROUND: Postoperative microvascular arterial vasospasm is a rare clinical entity. There are no published management algorithms and also the pathophysiology of this phenomenon has not been elucidated. METHODS: An email survey of American Society for Reconstructive Microsurgery (ASRM) and World Society for Reconstructive Microsurgery (WSRM) members regarding their experiences with postoperative arterial vasospasm was conducted, returning 116 responses. A comprehensive literature search was conducted regarding the current body of knowledge on this entity. RESULTS: Sixty-five percent of respondents encountered cases where postoperative arterial vasospasm was clearly the cause of flap ischemia. The majority (62%) of surgeons believed a damaged segment of the artery was responsible for the spasm, with technical issues cited as the most likely cause. Sixty-two percent and 50% of surgeons used segmental resection of the recipient and donor vessels, respectively.Rated for proclivity to vasospasm, superficial inferior epigastric artery (SIEA) was the flap, superior thyroid artery (STA) the recipient vessel, and the lower limb the anatomic region most frequently mentioned.Most widely used management strategies were: topical vasodilators (91%), adventitial stripping (82%), and dilation of recipient and donor vessels (76%). Over 50% of surgeons used some type of vessel resection technique. CONCLUSIONS: When flap ischemia is encountered without mechanical issues or thrombus, vasospasm can be the root cause. Certain vessels (SIEA, STA) and anatomic regions (lower limb) pose a higher risk for this phenomenon. When a vessel is affected, it is common practice to excise the questionable segment and use a graft as needed. Vessel resection as part of a multimodal approach can result in a reasonable salvage rate.

Postpartum hemorrhage from non-uterine arteries: clinical importance of their detection and the results of selective embolization.

Background Identification of the source of postpartum hemorrhage (PPH) is important for embolization because PPH frequently originates from non-uterine arteries. Purpose To evaluate the clinical importance of identifying the non-uterine arteries causing the PPH and the results of their selective embolization. Material and Methods This retrospective study enrolled 59 patients who underwent embolization for PPH from June 2009 to July 2016. Angiographic findings and medical records were reviewed to determine whether non-uterine arteries contributed to PPH. Arteries showing extravasation or hypertrophy accompanying uterine hypervascular staining were regarded as sources of the PPH. The results of their embolization were analyzed. Results Of 59 patients, 19 (32.2%) underwent embolization of non-uterine arteries. These arteries were ovarian (n = 7), vaginal (n = 5), round ligament (n = 5), inferior epigastric (n = 3), cervical (n = 2), internal pudendal (n = 2), vesical (n = 1), and rectal (n = 1) arteries. The embolic materials used included n-butyl cyanoacrylate (n = 9), gelatin sponge particles (n = 8), gelatin sponge particles with microcoils (n = 1), and polyvinyl alcohol particles (n = 1). In 13 patients, bilateral uterine arterial embolization was performed. Re-embolization was performed in two patients with persistent bleeding. Hemostasis was achieved in 17 (89.5%) patients. Two patients underwent immediate hysterectomy due to persistent bleeding. One patient experienced a major complication due to pelvic organ ischemia. One patient underwent delayed hysterectomy for uterine infarction four months later. Conclusion Non-uterine arteries are major sources of PPH. Detection and selective embolization are important for successful hemostasis.

Increased Lower Extremity Venous Stasis May Contribute to Deep Venous Thrombosis Formation after Microsurgical Breast Reconstruction-An Ultrasonographic Study.

Background Despite guideline-compliant prophylaxis, an increased rate of deep venous thrombosis (DVT) formation has been reported following autologous versus implant-based breast reconstruction. We hypothesized that tight abdominal fascia closure might decrease lower extremity venous return and promote venous stasis. Methods An observational crossover study of patients who underwent autologous breast reconstruction using transverse rectus abdominis musculocutaneous/deep inferior epigastric artery perforator flaps was conducted. Ultrasonographic measurements of the left common femoral vein (CFV) and right internal jugular vein (IJV) were performed preoperatively, in the postanesthesia care unit, and on postoperative day (POD) 1. Parameters of interest included vessel diameter, circumference, area, and maximum flow velocity. Results Eighteen patients with a mean age and body mass index of 52.7 years (range, 29-76 years) and 31.3 kg/m2 (range, 21.9-43.4 kg/m2) were included, respectively. A 29.8% increase in CFV diameter was observed on POD 1 (p < 0.0001). Similarly, a 24.3 and 69.9% increase in CFV circumference (p = 0.0007) and area (p < 0.0001) were noted, respectively. These correlated with a 28.4% decrease in maximum flow velocity in the CFV (p = 0.0001). Of note, none of these parameters displayed significant changes for the IJV, thus indicating that observed changes in the CFV were not the result of changes in perioperative fluid status. Conclusion Postoperative changes observed in the CFV reflect increased lower extremity venous stasis after microsurgical breast reconstruction and may contribute to postoperative DVT formation.

The position of 'shunt restriction' along an arterialized vein affects venous congestion and flap perfusion of an arterialized venous flap.

UNLABELLED: Restriction of arteriovenous (AV) shunting has been shown to enhance peripheral perfusion and also reduce venous congestion of an arterialized venous flap. Thus, this study is designed to investigate the effect of 'shunt-restriction' location on venous congestion and flap perfusion in a 'shunt-restricted' arterialized venous flap (AVF). METHODS: Abdominal flaps based on the thoracoepigastric vessels of Sprague-Dawley rats were raised. The inferior epigastric vein was repaired to the femoral artery in order to create an AVF. The superior epigastric vein was preserved for drainage. Microcirculation and laser Doppler flowmetry results were compared between AVFs with 'shunt restriction' at a proximal third (SR-proximal) distance and 'shunt restriction' at a distal third (SR-distal) distance. RESULTS: Bidirectional sluggish flow was detected at the proximal part of venous flaps in both groups. Unidirectional normal flow was observed in more capillaries of the distal flaps in the SR-proximal group. In the middle of the flaps, blood flow was sluggish and intermittent in the veins and was absent in most capillaries of the SR-distal group. The flow was prompt and unidirectional in more capillaries of the SR-proximal group. Using laser Doppler flowmetry, the average perfusion of the whole SR-proximal flaps was found to be higher than that of SR-distal flaps (p = 0.017). The average flux at the middle and distal portions of the SR-proximal group was significantly higher than those of the SR-distal group (p = 0.049). CONCLUSION: 'Shunt restriction' at the proximal third of the AV shunt resulted in enhanced perfusion and reduced venous congestion in an AVF.

Vascular smooth muscle desensitization in rabbit epigastric and mesenteric arteries during hemorrhagic shock.

The decompensatory phase of hemorrhage (shock) is caused by a poorly defined phenomenon termed vascular hyporeactivity (VHR). VHR may reflect an acute in vivo imbalance in levels of contractile and relaxant stimuli favoring net vascular smooth muscle (VSM) relaxation. Alternatively, VHR may be caused by intrinsic VSM desensitization of contraction resulting from prior exposure to high levels of stimuli that temporarily adjusts cell signaling systems. Net relaxation, but not desensitization, would be expected to resolve rapidly in an artery segment removed from the in vivo shock environment and examined in vitro in a fresh solution. Our aim was to 1) induce shock in rabbits and apply an in vitro mechanical analysis on muscular arteries isolated pre- and postshock to determine whether VHR involves intrinsic VSM desensitization, and 2) identify whether net VSM relaxation induced by nitric oxide and cyclic nucleotide-dependent protein kinase activation in vitro can be sustained for some time after relaxant stimulus washout. The potencies of phenylephrine- and histamine-induced contractions in in vitro epigastric artery removed from rabbits posthemorrhage were decreased by ∼0.3 log units compared with the control contralateral epigastric artery removed prehemorrhage. Moreover, a decrease in KCl-induced tonic, relative to phasic, tension of in vitro mesenteric artery correlated with the degree of shock severity as assessed by rates of lactate and K(+) accumulation. VSM desensitization was also caused by tyramine in vivo and PE in vitro, but not by relaxant agents in vitro. Together, these results support the hypothesis that VHR during hemorrhagic decompensation involves contractile stimulus-induced long-lasting, intrinsic VSM desensitization.

The evolution of perforator flap breast reconstruction: twenty years after the first DIEP flap.

It is over 20 years since the inaugural deep inferior epigastric perforator (DIEP) flap breast reconstruction. We review the type of flap utilized and indications in 2,850 microvascular breast reconstruction over the subsequent 20 years in the senior author's practice (Robert J. Allen). Data were extracted from a personal logbook of all microsurgical free flap breast reconstructions performed between August 1992 and August 2012. Indication for surgery; mastectomy pattern in primary reconstruction; flap type, whether unilateral or bilateral; recipient vessels; and adjunctive procedures were recorded. The DIEP was the most commonly performed flap (66%), followed by the superior gluteal artery perforator flap (12%), superficial inferior epigastric artery perforator flap (9%), inferior gluteal artery perforator flap (6%), profunda artery perforator flap (3%), and transverse upper gracilis flap (3%). Primary reconstruction accounted for 1,430 flaps (50%), secondary 992 (35%), and tertiary 425 (15%). As simultaneous bilateral reconstructions, 59% flaps were performed. With each flap, there typically ensues a period of enthusiasm which translated into surge in flap numbers. However, each flap has its own nuances and characteristics that influence patient and physician choice. Of note, each newly introduced flap, either buttock or thigh, results in a sharp decline in its predecessor. In this practice, the DIEP flap has remained the first choice in autologous breast reconstruction.

The new technique of using the epigastric arteries in renal transplantation with multiple renal arteries.

The most common anatomic variant seen in the donor kidneys for renal transplantation is multiple renal arteries (MRA), which can cause an increased risk of complications. We describe the long-term outcomes of 16 years of experience in 76 kidney transplantations with MRAs. In a new reconstruction technique, we remove arterial clamps after anastomosing the donor to the recipient's main renal vessels, which cause backflow from accessory arteries to prevent thrombosis. By this technique, we reduce the ischemic times as well as the operating times. Both in live or cadaver donor kidneys, lower polar arteries were anastomosed to the inferior epigastric artery and upper polar arteries were anastomosed to the superior epigastric arteries. Injection of Papaverine and ablation of sympathic nerves of these arteries dilate and prevent them from post-operative spasm. Follow-up DTPA renal scan in all patients showed good perfusion and function of the transplanted kidney, except two cases of polar arterial thrombosis. Mean creatinine levels during at least two years of follow-up remained acceptable. Patient and graft survival were excellent. No cases of ATN, hypertension, rejection and urologic complications were found. In conclusion, this technique can be safely and successfully utilized for renal transplantation with kidneys having MRAs, and may be associated with a lower complication rate and better graft function compared with the existing techniques.

Arterial stiffness and functional properties in chronic kidney disease patients on different dialysis modalities: an exploratory study.

BACKGROUND: Abnormalities of vascular function and accumulation of oxidative stress have been associated with chronic kidney disease (CKD). Dialysis modalities, peritoneal dialysis (PD) and haemodialysis (HD) may differentially impact on vascular function and oxidative stress. METHODS: Patients undergoing living donor transplantation were studied for vascular stiffness using pulse wave velocity measurements, and inferior epigastric arteries were harvested to examine in vitro stiffness and functional properties and evidence of oxidative stress. Forty-one patients were studied representing PD (n = 12), HD (n = 14) and non-dialysed recipients (n = 15). RESULTS: We demonstrated differences in stiffness from in vivo and in vitro measurements such that non-dialysis < HD < PD groups. The stiffness measurements did not correlate with duration of CKD nor dialysis duration, but did so with phosphate levels (r = 0.356, P = 0.02). From the in vitro isometric force experiments, HD arteries demonstrated decreased contractility and endothelium-dependent relaxation compared with PD and non-dialysis vessels. Level of oxidative stress (as indicated by the 8-isoprostane level) was 30% higher in HD arteries than in PD arteries. Protein expression of inducible nitric oxide synthase, NADPH subunits and xanthine oxidase was upregulated in HD arteries, while superoxide dismutase was downregulated. The compromised vascular function in HD arteries was improved by pharmacological means that eliminated oxidative stress. CONCLUSIONS: We report associations between vasomotor function and oxidative stress in the vasculature of patients receiving different dialysis therapies. Oxidative stress, which may be differentially augmented during PD and HD, may play an important role in the vascular dysfunction in dialysis populations.

Clinical applications of the superior epigastric artery perforator (SEAP) flap: anatomical studies and preoperative perforator mapping with multidetector CT.

BACKGROUND: Pedicled superior epigastric artery perforator (SEAP) flaps can be raised to cover challenging thoracic defects. We present an anatomical study based on multidetector computerized tomography (MDCT) scan findings of the SEA perforators in addition to the first reported clinical series of SEAP flaps in anterior chest wall reconstruction. MATERIAL AND METHODS: (a) In the CT scan study, images of a group of 20 patients who underwent MDCT scan analysis were used to visualise bilaterally the location of musculocutaneous SEAP. X- and Y-axes were used as landmarks to localise the perforators. The X-axis is a horizontal line at the junction of sternum and xyphoid (JCX) and the Y-axis is at the midline. (b) In the clinical study, seven pedicled SEAP flaps were performed in another group of patients. RESULTS: MDCT images revealed totally 157 perforators with a mean of 7.85 perforators per patient. The dominant perforators (137 perforators) were mainly localised in an area between 1.5 and 6.5 cm from the X-axis on both sides and between 3 and 16 cm below the Y-axis. The calibre of these dominant perforators was judged as 'good' to 'very good' in 82.5% of the cases. The average dimension of the flap was 21.7x6.7 cm. All flaps were based on one perforator. Mean harvesting time was 110 min. There were no flap losses. Minor tip necrosis occurred in two flaps. One of them was treated with excision and primary closure. CONCLUSION: Our clinical experience indicates that the SEAP flap provides a novel and useful approach for reconstruction of anterior chest wall defects. CT-based imaging allows for anatomical assessment of the perforators of the superior epigastric artery (SEA).

Early detection of flap failure using a new thermographic device.

BACKGROUND: Early recognition of perfusion failure is critical for free flap salvage. However, most of the different methods assessing perfusion have limitations and have not gain widespread acceptance. The aim of this study was to evaluate a novel system, a combination of a highly sensitive infrared camera with dynamic infrared image processing, in an animal flap model. MATERIALS AND METHODS: Flaps based on the inferior superficial epigastric vessels were raised bilaterally in 20 rats. One pedicle artery or vein was ligated and the contralateral side served as unligated control. Thermographic measurements were performed before and after ligation yielding a color map and a temperature recording. The macroscopic evolution of the flap was photographically documented. RESULTS: All vascular occlusions were rapidly detected. In the artery ligated group, the disappearance of the hot spot, corresponding to the pedicle, was observed in absence of macroscopic changes of the flap. In animals undergoing venous ligation, changes in the thermographic image preceded clinical signs of congestion. Temperature recordings between arterial and venous ligation were not significantly different. CONCLUSIONS: Vascular compromise was rapidly and consistently identified prior to appearance of macroscopic changes. This very sensitive system allows for a precise detection of small differences of infrared emission within the flap visualized as changes in the color map with disappearance of the hot spot on the color map. This is independent of absolute temperature values that are influenced by environmental factors. In addition to postoperative monitoring, the set-up may be a promising tool for preoperative planning of perforator flaps.

Flap size/flow rate relationship in perforator flaps and its importance in DIEAP flap drainage.

The vascular architecture within a perforator flap is different from a conventional muscle or myocutaneous flap. The purpose of this paper is to understand the correlation between flow rate and flap size in perforator flaps. With extrapolation of these data, we have provided an indirect analysis of the venous drainage and its correlation with flap size. A prospective study was planned. Twenty-five patients were enrolled in this study: six patients were operated on using an anterolateral thigh (ALT) flap and 19 using a deep inferior epigastric artery perforator (DIEAP) flap. One month postoperatively, echo-colour-Doppler measurements were performed on pedicle and perforator arteries to calculate blood flow rate in the flaps. A correlation between weight and flow rate was analysed. Spearman rho statistic was calculated. A linear regression model was made from patient data of flow rate/flap weight and predicted values of flow per flap weight were calculated. Then, flow rate values of veins of various diameters were estimated using Hagen-Poiseuille's formula. Our data show that flow rate measured postoperatively on flap arteries is significantly correlated with flap weight [rho(23 d.f.)=0.725, P<0.01 (two-tailed)]. Moreover, we have calculated the minimum size of veins able to drain flaps of increasing weights with different patterns, i.e. our data show that veins of 1.30, 1.50 and 1.75 mm diameter could safely drain flaps of, respectively, 300, 500 and 900 g in weight. This can be useful preoperatively to estimate the risk of flap congestion and in planning additional drainage.

The abdominal adipofascial flap: a new model for direct in vivo observation of microcirculatory hemodynamics of the abdominal fat tissue in rat.

INTRODUCTION: The peripheral adipose tissue is a vital component of many procedures in reconstructive and esthetic surgery. There is a limited knowledge on hemodynamic changes of adipose tissue. A direct intravital microscopic observation method is needed for the measurement of microcirculatory changes occurring in peripheral fat tissue during different plastic surgical procedures. Here we are introducing a model allowing for the direct in vivo monitoring and measurements of microcirculatory hemodynamics of peripheral adipose tissue. METHODS: Eight male Lewis rats weighing between 150 and 180 g were used in this study. Eight abdominal adipofascial flaps based on the left femoral artery, vein, and nerve were dissected after excision of the skin of the groin and lower abdominal region. Flap angiography using Indian ink was performed to demonstrate vascular anatomy of the flap. Standard intravital microscopy was used to monitor hemodynamic parameters such as vascular diameters, functional capillary perfusion, and leukocyte-endothelial interactions. RESULTS: Under direct intravital microscopy, microcirculatory parameters including vascular diameters, capillary perfusion, and leukocyte-endothelial interaction behaviors of the abdominal adipofascial flaps were established. CONCLUSIONS: We have showed feasibility of monitoring microcirculatory hemodynamics of the abdominal adipofascial flap model in rat. This model can be applied for intravital recordings of peripheral adipose tissue physiology and in different research scenarios such as the effects of ischemia reperfusion injury, effects of surgical trauma and wound healing studies with application of different pharmacologic agents and treatment protocols.