Area Of Scar Tissue Research Articles

Scar Extension Measured by Magnetic Resonance–Based Signal Intensity Mapping Predicts Ventricular Tachycardia Recurrence After Substrate Ablation in Patients With Previous Myocardial Infarction

ObjectivesThe aim of this study was to determine if noninvasive measurement of scar by contrast-enhanced magnetic resonance imaging (MRI)–based signal intensity (SI) mapping predicts ventricular tachycardia (VT) recurrence after endocardial ablation. BackgroundScar extension on voltage mapping predicts VT recurrence after ablation procedures. MethodsA total of 46 consecutive patients with previous myocardial infarction (87% men, mean age 68 ± 9 years, mean left ventricular ejection fraction 36 ± 10%) who underwent VT substrate ablation before the implantation of a cardioverter-defibrillator were included. Before ablation, contrast-enhanced MRI was performed, and areas of endocardial and epicardial scarring and heterogeneous tissue were measured; averaged subendocardial and subepicardial signal intensities were projected onto 3-dimensional endocardial and epicardial shells in which dense scar, heterogeneous tissue, and normal tissue were differentiated. ResultsDuring a mean follow-up period of 32 ± 24 months 17 patients (37%) had VT recurrence. Patients with recurrence had larger scar and heterogeneous tissue areas on SI maps in both endocardium (81 ± 27 cm2 vs. 48 ± 21 cm2 [p = 0.001] and 53 ± 21 cm2 vs. 30 ± 15 cm2 [p = 0.001], respectively) and epicardium (76 ± 28 cm2 vs. 51 ± 29 cm2 [p = 0.032] and 59 ± 25 cm2 vs. 37 ± 19 cm2 [p = 0.008]). In the multivariate analysis, MRI endocardial scar extension was the only independent predictor of VT recurrence (hazard ratio: 1.310 [per 10 cm2]; 95% confidence interval: 1.051 to 1.632; p = 0.034). Freedom from VT recurrence was higher in patients with small endocardial scars by MRI (<65 cm2) than in those with larger scars (≥65 cm2) (85% vs. 20%, log-rank p = 0.018). ConclusionsPre-procedure endocardial scar extension assessment by contrast-enhanced MRI predicts VT recurrence after endocardial substrate ablation. This information may be useful to select patients for ablation procedures.

Histological Evaluation of Regenerated Semitendinosus Tendon a Minimum of 6 Years After Harvest for Anterior Cruciate Ligament Reconstruction

Background:Semitendinosus (ST) and/or gracilis (G) autografts are the most used grafts for anterior cruciate ligament (ACL) surgery. The tendons have been shown to be able to regenerate but with focal areas of scar tissue in the short term. There are no long-term histological studies of the regenerated tendons.Hypothesis:In the long term, the regenerated ST tendon normalizes and has a similar histology as the contralateral nonharvested tendon.Study Design:Case-control study; Level of evidence, 3.Methods:Eighteen patients (8 female, 10 male) who underwent ACL surgery using ipsilateral ST/G tendon autografts were included in this study. Percutaneous specimens were obtained from the regenerated ST tendon and the contralateral nonharvested ST tendon under ultrasonographic guidance at a median of 8.4 years (100.5 months; range, 77-129 months) after the harvest procedure. Specimens from the nonoperated side served as controls. The histology and presence of glycosaminoglycans (GAGs) were assessed using a light microscope and a semiquantitative grading system.Results:Thirty-six biopsies were obtained (2 biopsies from each patient). In 5 biopsies, the amount of tissue was too small to analyze in the light microscope, and 1 patient had been operated on bilaterally and was therefore excluded. In total, 24 biopsies were included in the histological analysis. In overall terms, there were no significant differences between the regenerated and nonharvested ST tendon in terms of fiber structure, cellularity, vascularity, and level of GAGs a minimum 6 years after harvest of the ST tendon. However, 3 of the regenerated tendons displayed a loss of fiber structure.Conclusion:The ST tendon regenerates and may regain a histological appearance similar to that of the nonharvested contralateral tendon, as seen in this study a median of 8.4 years after harvesting. However, in some tendons, loss of fiber structure was found.

Laser-Supported CD133+ Cell Therapy in Patients with Ischemic Cardiomyopathy: Initial Results from a Prospective Phase I Multicenter Trial

ObjectivesThis study evaluates the safety, principal feasibility and restoration potential of laser-supported CD133+ intramyocardial cell transplantation in patients with ischemic cardiomyopathy.MethodsForty-two patients with severe ischemic cardiomyopathy (left ventricular ejection fraction (LVEF) >15% and <35%) were included in this prospective multicenter phase I trial. They underwent coronary artery bypass grafting (CABG) with subsequent transepicardial low-energy laser treatment and autologous CD133+ cell transplantation, and were followed up for 12 months. To evaluate segmental myocardial contractility as well as perfusion and to identify the areas of scar tissue, cardiac MRI was performed at 6 months and compared to the preoperative baseline. In addition, clinical assessment comprising of CCS scoring, blood and physical examination was performed at 3, 6 and 12 months, respectively.ResultsIntraoperative cell isolation resulted in a mean cell count of 9.7±1.2×106. Laser treatment and subsequent CD133+ cell therapy were successfully and safely carried out in all patients and no procedure-related complications occurred. At 6 months, the LVEF was significantly increased (29.7±1.9% versus 24.6±1.5% with p = 0.004). In addition, freedom from angina was achieved, and quality of life significantly improved after therapy (p<0.0001). Interestingly, an extended area of transmural delayed enhancement (>3 myocardial segments) determined in the preoperative MRI was inversely correlated with a LVEF increase after laser-supported cell therapy (p = 0.024).ConclusionsThis multicenter trial demonstrates that laser-supported CD133+ cell transplantation is safe and feasible in patients with ischemic cardiomyopathy undergoing CABG, and in most cases, it appears to significantly improve the myocardial function. Importantly, our data show that the beneficial effect was significantly related to the extent of transmural delayed enhancement, suggesting that MRI-guided selection of patients is mandatory to ensure the effectiveness of the therapy.Trial Registration:EudraCT 2005-004051-35) Controlled-Trials.com ISRCTN49998633

Heterotopic ossification following surgery: an unusual cause of resuscitation injury

Case reportA 55-year-old male with a medical history of cerebrovas-cular accident, coronary artery bypass grafting, type IIdiabetes mellitus, and infection of the leg (following cor-onary bypass grafting), collapsed after sexual intercourse.Resuscitation was unsuccessful.At autopsy, a healed vertical thoracotomy scar extend-ing to the xiphisternum, associated with underlying denseperi- and epicardial fibrous adhesions was found. Patentcoronary artery bypass grafts were connected to the leftanterior and posterior descending coronary arteries, withthe distal native vessels demonstrating marked atheroscle-rosis with significant stenosis. Myocardial fibrosis with fullthickness scarring of the left ventricular free wall wasconfirmed microscopically, with no evidence of acuteischemic myocardial damage. An area of previous ischemicinjury was identified in the right basal ganglia of the brain.There were no injuries; toxicology and biochemistry testswere unremarkable. No other underlying organic illnesseswere present which could have caused or contributed todeath. Death was therefore attributed to ischemic heartdisease.Also noted at autopsy were multiple rib fractures and alaceration of the liver, the results of attempts at resuscita-tion. Specifically, there were recent fractures (withoutintercostal muscle/soft tissue hemorrhage) of the second toseventh ribs on the left, and the second to ninth ribs on theright, in the mid-clavicular lines. Within the abdomen therewas a 3 cm long vertical laceration of the anterior surfaceof the left lobe of the liver in the midline, which extendedto a depth of approximately 1 cm (Fig. 1). There wassubcapsular bruising surrounding the tear but no intra-abdominal bleeding. Histological examination of samplesfrom the region of the laceration revealed no inflammatoryreaction.Of note, the liver laceration had been caused by a3.5 cm bony spur that projected downwards from thexiphisternum (Fig. 2). The bony spicule measuredapproximately 0.3 cm in diameter and ended in a terminalnodule 0.5 cm in diameter (Fig. 3). The bone spur hadarisen from heterotopic ossification within an area of densefibrous scar tissue associated with the previous coronaryartery bypass surgery. This calcified extension had causedthe tear in the liver when resuscitation was performed.Radiography confirmed the bony nature of the tissue(Fig. 4) and that it was not an extension of the wire suturethat had been used to close the sternum after cardiacsurgery.DiscussionHeterotopic ossification refers to the phenomenon of boneformation within extraskeletal soft tissues or organs. It canfollow trauma, surgery or burns, as well as being found incertain genetic disorders [1, 2]. It may also arise in bothbenign and malignant tumors, the latter caused by possiblestromal fibroblast metaplasia [3]. Heterotopic ossificationhas to be distinguished from extraskeletal or metastaticosteosarcoma as the pathogenesis and prognosis areentirely different [4, 5].

Refining perforator selection for deep inferior epigastric perforator flap: The impact of the dominant venous perforator

This article aims to investigate the critical role of the venous-perforator in the decision-making process of choosing the best suitable perforator-complex in a deep inferior epigastric perforator (DIEP) flap. Forty consecutive DIEP breast reconstructions were pre-operatively evaluated by CT-Angiography to identify the dominant and centrally located abdominal wall perforators. The CTA results were used as a guide to conduct a Color-Duplex-Ultrasound examination that was mainly focused on investigating the accompanying venous-perforator. In group-A (n = 20) perforator-complex selection was based on the size of the arterial-perforator, whilst in group-B (n = 20) it was based on the size of the venous-perforator. All single perforator-complex DIEP flaps survived. No significant differences were recorded concerning the size of arterial-perforator between the two groups; however the size of venous-perforator was significantly larger in group-B (P < 0.05). In group-A, four flaps showed vascular compromise intraoperative that was salvaged by flap supercharge with the superficial inferior epigastric system. In contrast, in group-B, all flaps were re-vascularized uneventfully (P < 0.05). Physical examination revealed a palpable mass in one patient and ultrasound investigation added three cases with a firm area of scar tissue in group-A, but no fat necrosis was detected in group-B (P < 0.05). The CTA-guided duplex ultrasonography could direct the perforator-complex selection according to the size of the venous-perforator, and may reduce the intraoperative problems and the incidence of fat necrosis.

COMPARISON OF THE ACUTE INFLAMMATORY RESPONSE AND PROLIFERATION OF DRY NEEDLING AND ELECTROLYSIS PERCUTANEOUS INTRATISSUE (EPI) IN HEALTHY RAT ACHILLES TENDONS

IntroductionElectrolysis Percutaneous Intratissue (EPI) is a new technique that involves the application of a galvanic current with an acupuncture needle that causes a theoretical local inflammatory process and subsequent tissue...

A Connexin43 Mimetic Peptide Promotes Regenerative Healing and Improves Mechanical Properties in Skin and Heart

Evidence is building that the gap junction protein connexin43 (Cx43) is an important molecule in regenerative healing of skin and heart. Excess scarring from skin wound healing is a continuing clinical problem. Humans generally lack the ability to regenerate tissue following injury, and some degree of fibrotic repair occurs. In the skin, this results in unsightly scars with inferior mechanical properties. In the heart, scarring causes disruption in the contractility of cardiac muscle and increases the risk of deadly arrhythmia. Therapies that tip the balance of wound healing away from scar tissue and toward regeneration would thus represent a significant medical advance. A cell-permeant peptide, αCT1 (alpha connexin carboxyl-terminal peptide), based on the carboxyl-terminus of connexin43, has been shown to elicit changes in gap junction organization and intracellular communication. In the skin, αCT1 applied at acute time points results in decreased inflammatory response, reduced area of scar progenitor tissue, and restoration of more normal dermal structure and mechanical strength. αCT1 application to infarcted hearts improved cardiac contractility, reduced the propensity for arrhythmia, and increased conduction velocity through the injured heart. Application of therapies like αCT1 could reduce cutaneous scarring and improve mechanical properties of healed skin and the contractile function and electrical stability of the heart following injury or surgery. αCT1 is a potential therapy for cutaneous wounds that could lead to reduced scarring and improvements in the mechanical properties of healed skin. For injured myocardial tissues, this Cx43 mimetic peptide may also provide a therapeutic approach for targeting pathological fibrosis and reducing the likelihood of sudden death from cardiac arrhythmias.

Myocardial Connective Tissue Growth Factor (CCN2/CTGF) Attenuates Left Ventricular Remodeling after Myocardial Infarction

AimsMyocardial CCN2/CTGF is induced in heart failure of various etiologies. However, its role in the pathophysiology of left ventricular (LV) remodeling after myocardial infarction (MI) remains unresolved. The current study explores the role of CTGF in infarct healing and LV remodeling in an animal model and in patients admitted for acute ST-elevation MI.Methods and ResultsTransgenic mice with cardiac-restricted overexpression of CTGF (Tg-CTGF) and non-transgenic littermate controls (NLC) were subjected to permanent ligation of the left anterior descending coronary artery. Despite similar infarct size (area of infarction relative to area at risk) 24 hours after ligation of the coronary artery in Tg-CTGF and NLC mice, Tg-CTGF mice disclosed smaller area of scar tissue, smaller increase of cardiac hypertrophy, and less LV dilatation and deterioration of LV function 4 weeks after MI. Tg-CTGF mice also revealed substantially reduced mortality after MI. Remote/peri-infarct tissue of Tg-CTGF mice contained reduced numbers of leucocytes, macrophages, and cells undergoing apoptosis as compared with NLC mice. In a cohort of patients with acute ST-elevation MI (n = 42) admitted to hospital for percutaneous coronary intervention (PCI) serum-CTGF levels (s-CTGF) were monitored and related to infarct size and LV function assessed by cardiac MRI. Increase in s-CTGF levels after MI was associated with reduced infarct size and improved LV ejection fraction one year after MI, as well as attenuated levels of CRP and GDF-15.ConclusionIncreased myocardial CTGF activities after MI are associated with attenuation of LV remodeling and improved LV function mediated by attenuation of inflammatory responses and inhibition of apoptosis.

The Effect of Platelet-Rich Plasma on Normal Soft Tissues in the Rabbit

Platelet-rich plasma is reported to contain multiple growth factors, and has been utilized in orthopaedic surgery to aid healing in multiple tissues. To date, the use of autologous platelet-rich plasma has not been studied for its effects on normal soft tissue. Eighteen adult New Zealand White rabbits were injected with 0.5 mL of autologous platelet-rich plasma in the right or left quadriceps muscle, Achilles tendon, medial collateral ligament, subcutaneous tissue, tibial periosteum, and ankle joint. Saline solution was injected on the contralateral side as a control. The soft tissues were examined histologically at two weeks (six rabbits) and six weeks (six rabbits), and soft tissues from six rabbits that had been reinjected at six weeks were examined at twelve weeks. Inflammatory skin lesions were visible at forty-eight hours at superficial platelet-rich plasma sites. All lesions resolved by six days. Compared with findings in control specimens, histological analysis of platelet-rich plasma injection sites at two weeks showed a marked inflammatory infiltrate with lymphocytic and monocytic predominance. Intra-articular injection showed villous synovial hyperplasia and chronic synovitis. Tendon and ligament sites showed new collagen deposition. Intramuscular injection sites showed thrombosis, necrosis, and calcium deposition. Subcutaneous sites also showed calcium deposition without necrosis as well as collagen nodules representing early scar tissue. Histological examination of platelet-rich plasma injection sites at six and twelve weeks demonstrated a persistent but diminished inflammatory infiltrate. Focal areas of scar tissue were seen with fibroblasts, collagen formation, and neovascularity. All saline solution sites at all times were nonreactive. Platelet-rich plasma can initiate an inflammatory response in the absence of an inciting injury in normal soft tissue in rabbits.

Reply to Poullis

We read Dr Poullis’s letter addressing our article with great interest [1]. Firstly, we would like to clarify that our article was not meant to be a head-to-head comparison with the patients in the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Our patients were significantly younger than the Western population comprising the STICH trial. This is due to the incidence of coronary artery disease at a younger age in the Indian population, due to various ethnic predisposing factors. Our patients mostly had single-vessel disease involving the Left Anterior Descending Coronary Artery (LAD), although some had two- and three-vessel disease. Those patients with multivessel disease received multiple grafts. The pathophysiology of left ventricular aneurysm has been seen in predominantly single coronary artery territory involvement [2], which may often be recanalized and therefore not requiring revascularization, with only resection of scar tissue and reshaping of the contractile myocardium providing adequate clinical benefit. The immediate and 30-day postoperative functional class has been mentioned in the table. The re-hospitalization for heart failure occurred at 9.2 1.2 months following surgery. The reasons for this were multi-factorial and related to associated pulmonary hypertension and renal dysfunction, and not to the surgical technique per se. Postoperatively, all patients were on maximally tolerated doses of beta-blockers, ace inhibitors, statins, aspirin, and diuretics. The dosages of diuretics and ace inhibitors, however, decreased significantly following surgery. We had centerline analysis of contrast ventriculography of all our patients before and after surgery. All our patients had discrete areas of dyskinesis/akinesis at baseline conforming to the definition of left ventricular aneurysm. Following surgery, there was a significant decrease in hypokinetic chords from 61.1 12.8 to 36.5 14.8 ( p < 0.001) [3]. This was in the anterior and anterolateral segments in anterior aneurysms and in the inferior and inferbasal segments of the inferior aneurysms. There was also a significant decrease in akinetic/dyskinetic chords from 32.5 11 at baseline to 25 8.1 following surgery ( p < 0.001). Here, the akinetic/ dyskinetic chords in the postoperative ventricle conformed to the intracavitary patch which remained akinetic. We agree with Dr Poullis that the success of surgical ventricular restoration (SVR) depends on the presence of discrete areas of akinesis/dyskinesis, conforming to scar tissue and definite areas of contractile myocardium. For patients with diffusely hypokinetic ventricles, the only option would be cardiac transplantation, if eligible. This has been adequately described in our article [4]. Our study follows Pocar et al. [5] in validating the surgical techniques resulting in a more ellipsoid ventricular geometry. Our left ventricular shape analysis also proved significantly better alignment of the contractile myocardial fibers in the anterior wall, which was not seen with endoventricular circular patch plasty [6]. In our patients, despite a postoperative decrease in left ventricular stroke volume, there was a significant clinical improvement as assessed by functional class, which cannot be attributed to decreased contractility. This has also been proved by our centerline analysis and shape analysis. The heart rate did not change significantly following surgery (baseline heart rate (HR): 84 3 beats per minute (BPM) to postoperative HR: 81 4 BPM). The phenomenon of decreasing stroke volume following SVR will be the subject of future study.

Diminished Type III Collagen Promotes Myofibroblast Differentiation and Increases Scar Deposition in Cutaneous Wound Healing

The repair of cutaneous wounds in the postnatal animal is associated with the development of scar tissue. Directing cell activities to efficiently heal wounds while minimizing the development of scar tissue is a major goal of wound management and the focus of intensive research efforts. Type III collagen (Col3), expressed in early granulation tissue, has been proposed to play a prominent role in cutaneous wound repair, although little is known about its role in this process. To establish the role of Col3 in cutaneous wound repair, we examined the healing of excisional wounds in a previously described murine model of Col3 deficiency. Col3 deficiency (Col3+/–) in aged mice resulted in accelerated wound closure with increased wound contraction. In addition, Col3-deficient mice had increased myofibroblast density in the wound granulation tissue as evidenced by an increased expression of the myofibroblast marker, α-smooth muscle actin. In vitro, dermal fibroblasts obtained from Col3-deficient embryos (Col3+/– and –/–) were more efficient at collagen gel contraction and also displayed increased myofibroblast differentiation compared to those harvested from wild-type (Col3+/+) embryos. Finally, wounds from Col3-deficient mice also had significantly more scar tissue area on day 21 postwounding compared to wild-type mice. The effect of Col3 expression on myofibroblast differentiation and scar formation in this model suggests a previously undefined role for this ECM protein in tissue regeneration and repair.

Ablation of Ventricular Tachycardia in Patients with Ischemic Heart Disease Using Rotational Angiography (DynaCT) Guided Substrate Mapping Exclusively: Intermediate Term Results

Aim: We evaluated the safety, procedural efficacy and outcomes of ablation of Ventricular Tachycardia (VT) in Ischemic Heart Disease patients using Rotational Angiography and Electroanatomical 3D based substrate mapping strategy exclusively. Methods: Six consecutive patients with a history of MI and hemodynamically unstable drug resistant VT were studied. High-density electroanatomic mapping was performed during sinus rhythm using the NavX velocity (SJM) system. In four patients real time 3D reconstruction of Left Ventricle was done using DynaCT system (Seimens). The scar tissue (Local Voltage- 0.2–0.5 mV) and Low Voltage Areas (Local voltage- 0.5–1.5 mV) were identified. The RF ablation was performed using a 4 mm ablation catheter and the isthmus ablated in 4 patients whereas scar tissue isolation was done in 2 patients. VT induction was done only after RF ablation. Result: Post ablation the no VT was inducible. During the follow-up (18±3.9 months), spontaneous VT was not recorded in any patient on regular ICD interrogation. Conclusion: Substrate mapping can be used to identify the arrhythmogenic tissue and guide VT ablation. This therapeutic strategy may be considered routinely/increasingly in the management of patients with multiple hemodynamically unstable VTs. The use of real time 3D reconstruction (DynaCT) can increase the safety of the procedure.

Safe and Effective One-Session Fractional Skin Resurfacing Using a Carbon Dioxide Laser Device in Super-Pulse Mode: A Clinical and Histologic Study

Carbon dioxide (CO(2)) laser ablative fractional resurfacing produces skin damage, with removal of the epidermis and variable portions of the dermis as well as associated residual heating, resulting in new collagen formation and skin tightening. The nonresurfaced epidermis helps tissue to heal rapidly, with short-term postoperative erythema. The results for 40 patients (8 men and 32 women) after a single session of a fractional CO(2) resurfacing mode were studied. The treatments included resurfacing of the full face, periocular upper lip, and residual acne scars. The patients had skin prototypes 2 to 4 and wrinkle degrees 1 to 3. The histologic effects, efficacy, and treatment safety in various clinical conditions and for different phototypes are discussed. The CO(2) laser for fractional treatment is used in super-pulse mode. The beam is split by a lens into several microbeams, and super-pulse repetition is limited by the pulse width. The laser needs a power adaptation to meet the set fluence per microbeam. Laser pulsing can operate repeatedly on the same spot or be moved randomly over the skin, using several passes to achieve a desired residual thermal effect. Low, medium, and high settings are preprogrammed in the device, and they indicate the strength of resurfacing. A single treatment was given with the patient under topical anesthesia. However, the anesthesia was injected on areas of scar tissue. Medium settings (2Hz, 30W, 60mJ) were used, and two passes were made for dark skins and degree 1 wrinkles. High settings (2Hz, 60W, 120mJ) were used, and three passes were made for degree 3 wrinkles and scar tissue. Postoperatively, resurfaced areas were treated with an ointment of gentamycin, Retinol Palmitate, and DL-methionine (Novartis; Farmaceutics, S.A., Barcelona, Spain). Once epithelialization was achieved, antipigment and sun protection agents were recommended. Evaluations were performed 15days and 2months after treatment by both patients and clinicians. Treatment improved wrinkle aspect and scar condition, and no patient reported adverse effects or complications, irrespective of skin type, except for plaques of erythema in areas that received extra laser passes, which were not seen at the 2-month assessment. The results evaluated by clinicians were very much in correlation with those of patients. Immediately after treatment, vaporization was produced by stacked pulses, with clear ablation and collateral heat coagulation. An increased number of random pulses removed more epidermis, and with denser pulses per area, a thermal deposit was noted histologically. At 2months, a thicker, multicelluar epidermis and an evident increase in collagen were observed. Fractional CO(2) laser permits a variety of resurfacing settings that obtain safe, effective skin rejuvenation and correct scar tissue in a single treatment.

Study on the optimal concentration of topical mitomycin-C in preventing postlaminectomy epidural adhesion

There is increasing evidence that topical application of mitomycin-C can be beneficial in reducing epidural scar adhesion. However, the ideal concentration of mitomycin-C is unknown. The purpose of this study was to verify its efficacy for preventing epidural adhesion and the immediate electrophysiological responses caused by it in a laminectomy model. Seventy rats underwent laminectomy at L-1 and L-2. Cotton pads soaked with saline and various concentrations of mitomycin-C (0.1 mg/ml, 0.3 mg/ml, 0.5 mg/ml and 0.7 mg/ml) were applied to the exposed dura for 5 min. Spine somatosensory evoked potentials (SSEP) were monitored in preoperative and the immediate electrophysiological responses of mitomycin-C used. Four weeks postlaminectomy the rats were killed. The area of epidural scar tissue and degree of epidural adhesion were determined by 7.0T Micro MR imaging. Macroscopic evaluations were performed according to the Rydell standard. The results showed that severe epidural adhesion was formed in the saline group and no dural adherence or incomplete adhesions were found in the mitomycin-C group. The Rydell classification and the degree of epidural adhesion and the area of the scar in 0.5 mg/ml group and 0.7 mg/ml mitomycin-C group revealed a significant decrease compared with the control group and 0.1 mg/ml group and 0.3 mg/ml mitomycin-C group. The spine sensory evoked potentials did not alter obviously in both preoperative and the immediate electrophysiological responses of mitomycin-C used. In conclusion, locally applied mitomycin-C in a concentration of 0.5 mg/ml and 0.7 mg/ml mitomycin-C may be the optimal concentration in preventing postlaminectomy epidural adhesion.

Positron emission tomography; viable tool in patients pre-CABG?

Positron emission tomography; viable tool in patients pre-CABG?

Visualization of transcoronary ablation of septal hypertrophy in patients with hypertrophic obstructive cardiomyopathy: a comparison between cardiac MRI, invasive measurements and echocardiography

ObjectiveHypertrophic obstructive cardiomyopathy (HOCM) is treated by surgical myectomy or transcoronary ablation of septal hypertrophy (TASH). The aim of this study was to visualize the feasibility, success and short-term results of TASH on the basis of cardiac MRI (CMR) in comparison with cardiac catheterization and echocardiography.MethodsIn this in vivo study, nine patients with HOCM were treated with TASH. Patients were evaluated by transthoracic echocardiography, invasive cardiac angiography and CMR. Follow-up examinations were carried out after 1, 3 and 12 months. MR imaging was performed on a 1.5-T scanner. All images were processed using the semiautomatic Argus software and were evaluated by an attending thoracic radiologist and cardiologist.ResultsThe echocardiographic pressure gradient (at rest) was 69.3 ± 15.3 mmHg before and 22.1 ± 5.7 mmHg after TASH (P < 0.01, n = 9). The flux acceleration over the aortic valve examined (V max) was 5.1 ± 0.6 m/s before and 3.4 ± 0.3 m/s after the TASH procedure (P < 0.05). Also, there was a decrease of septum thickness from 22.0 ± 1.2 to 20.2 ± 1.0 mm (P < 0.05) after 6 ± 3 weeks. The invasively assessed pressure gradient at rest was reduced from 63.7 ± 15.2 to 21.2 ± 11.1 mmHg (P < 0.01) and the post-extrasystolic gradient was reduced from 138.9 ± 12.7 to 45.6 ± 16.5 mmHg (P < 0.01). All differences as well as the quantity of injected ethanol were plotted against the size or amount of scar tissue as assessed in the MRI. There was a statistically significant correlation between the post-extrasystolic gradient decrease and the amount of scar tissue (P = 0.03, r 2 = 0.5). In addition, the correlation between the quantity of ethanol and scar tissue area was highly significant (P < 0.01, r 2 = 0.6), whereas the values for the gradient deviation (P = 0.10, r 2 = 0.34), ΔV max (P = 0.12, r 2 = 0.31), as well as the gradient at rest (P = 0.27, r 2 = 0.17) were not significant.ConclusionTASH was consistently effective in reducing the gradient in all patients with HOCM. In contrast to the variables investigated by echocardiography, the invasively measured post-extrasystolic gradient correlated much better with the amount of scar tissue as assessed by CMR. We conclude that the optimal modality to visualize the TASH effect seems to be a combination of CMR and the invasive identification of the post-extrasystolic gradient.

Hypoxia Promotes Efficient Differentiation of Human Embryonic Stem Cells to Functional Endothelium

Early development of mammalian embryos occurs in an environment of relative hypoxia. Nevertheless, human embryonic stem cells (hESC), which are derived from the inner cell mass of blastocyst, are routinely cultured under the same atmospheric conditions (21% O(2)) as somatic cells. We hypothesized that O(2) levels modulate gene expression and differentiation potential of hESC, and thus, we performed gene profiling of hESC maintained under normoxic or hypoxic (1% or 5% O(2)) conditions. Our analysis revealed that hypoxia downregulates expression of pluripotency markers in hESC but increases significantly the expression of genes associated with angio- and vasculogenesis including vascular endothelial growth factor and angiopoitein-like proteins. Consequently, we were able to efficiently differentiate hESC to functional endothelial cells (EC) by varying O(2) levels; after 24 hours at 5% O(2), more than 50% of cells were CD34+. Transplantation of resulting endothelial-like cells improved both systolic function and fractional shortening in a rodent model of myocardial infarction. Moreover, analysis of the infarcted zone revealed that transplanted EC reduced the area of fibrous scar tissue by 50%. Thus, use of hypoxic conditions to specify the endothelial lineage suggests a novel strategy for cellular therapies aimed at repair of damaged vasculature in pathologies such as cerebral ischemia and myocardial infarction.

Fat Necrosis in Deep Inferior Epigastric Perforator Flaps: An Ultrasound-Based Review of 202 Cases

In autologous breast reconstruction after mastectomy, fat necrosis is a rather common complication that may lead to secondary corrective surgery. The understanding of fat necrosis until now has been limited because previous studies were based exclusively on physical examination and used diverse definitions. The authors retrospectively reviewed the incidence of fat necrosis and the correlation of several risk factors in 202 deep inferior epigastric perforator (DIEP) flaps for breast reconstruction. The incidence of fat necrosis was based on both physical examination and ultrasound imaging. The following risk factors were studied: age, smoking, body mass index, timing of reconstruction, and timing and extent of radiation therapy fields. Physical examination revealed a palpable mass or nodule in 14 percent of the DIEP flaps (28 of 202). Ultrasound examination added another 21 percent of DIEP flaps (42 of 202) with a firm area of scar tissue (diameter >or=5 mm). The overall ultrasound incidence of fat necrosis in this study was 35 percent (71 of 202). Although the overall ultrasound incidence of fat necrosis was very high, only 7 percent of the DIEP flaps (15 of 202) needed to undergo an extra surgical procedure for removal of this area. In contrast to previous studies, none of the risk factors studied was statistically significant for the occurrence of fat necrosis. These results suggest that there is no significant association between previously suspected risk factors and fat necrosis. The overall incidence of fat necrosis, however, is much higher than previously accepted, even though the need for corrective surgery is limited.

Different Substrates of Non-Sustained Ventricular Tachycardia in Post-infarction Patients With and Without Left Ventricular Dilatation

Background We investigated the relationship between nonsustained ventricular tachycardia (NSVT) and left ventricular (LV) dilatation, function, remodeling, and scar tissue extent in patients with previous myocardial infarction (MI). Methods and Results Eighty-two patients (ages 64 ± 10 years) with first previous MI were referred for 24-hour electrocardiogram recording and cine and delayed enhancement (DE) cardiac magnetic resonance (CMR). LV volumes, ejection fraction, systolic wall thickening, sphericity index, and core and peri-infarctual areas of scar tissue by CMR were evaluated. LV dilatation was observed in 39 patients. Episodes of NSVT were recorded in 32 patients: 23 with LV dilatation and 9 without. In the entire population, NSVT was related to ejection fraction, LV volumes, LV mass, and sphericity index; end-systolic volume ( P = .001) resulted in the only independent predictor at multivariate analysis. In patients without LV dilatation, the occurrence of NSVT was only positively related with percentage of contracting segments with DE ( P = .008). Conversely, in patients with LV dilatation, increase in LV mass ( P = .020) and end-systolic volume ( P = .038) were independent predictors of NSVT. Conclusions Necrotic and viable myocardium coexistence within the same wall segments predicted occurrence of NSVT in patients without LV dilatation, whereas LV mass and end-systolic volume were predictors of NSVT in those with LV dilatation.

Clinical Summaries

Clinical Summaries