Ajay Chavan - Academia.edu (original) (raw)

Papers by Ajay Chavan

Health Physics, 2021

Abstract The maximum annual radiation ocular dose limit for medical staff has been reduced to 20 ... more Abstract The maximum annual radiation ocular dose limit for medical staff has been reduced to 20 mSv in the current European directive 2013/59/Euratom. This multi-centric study aims at reporting the protected and unprotected eye lens doses in different fluoroscopically guided interventions and to evaluate any other factors that could influence the ocular dose. From July 2018 to July 2019, ocular radiation doses of six interventionists of four departments during complex interventions were recorded with a thermoluminescent dosimeter in front of and behind radiation protection glasses to measure the protected and unprotected doses. The position of personnel, intervention type, fluoroscopy time, total body dose and use of pre-installed protection devices like lead acrylic shields were also systematically recorded. Linear regression analysis was used to estimate the doses at 2 y and 5 y. The annual unprotected/protected ocular doses of six interventionists were 67/21, 32.7/3.3, 27.4/5.1, 7/0, 21.8/2.2, and 0/0 mSv, respectively. The unprotected dose crossed the 20-mSv annual limits for four interventionists and protected dose for one less experienced interventionist. The estimated 5-y protected ocular dose of this interventionist was 101.318 mSv (95%CI 96.066-106.57), also crossing the 5-y limit. The use of a lead acrylic shield was observed to have a significant effect in reducing ocular doses. The annual unprotected and protected ocular doses for interventionists dealing with complex interventions could cross the present permitted yearly limit. The measurement of significant protected ocular dose behind the radiation protection glasses emphasizes the additional indispensable role of pre-installed radiation protection devices and training in reducing radiation doses for complex procedures.

CardioVascular and Interventional Radiology, 2020

Journal of Thoracic Disease, 2018

Background: Surgical management of aortic arch diseases is one of the most challenging issues in ... more Background: Surgical management of aortic arch diseases is one of the most challenging issues in cardiovascular surgery. The aim of this study was to compare the outcome after frozen elephant trunk (FET) with conventional elephant trunk (ET) technique. Methods: Out of a total of 551 patients after thoracic aortic surgery, we analyzed 70 consecutive patients, who underwent aortic arch replacement with ET or FET technique between 2001 and 2017 in our institution. The patients were case-control matched in regard to such variables as age, sex, presence of an acute aortic dissection and necessity for concomitant procedures. The analysis included 25 patient pairs. Results: Among the 25 FET patients, eleven patients were female, the median age was 69, 15 (60%) patients had an aortic dissection and thirteen needed various concomitant procedures. In the second group, treated with conventional ET technique, 10 (40%) patients were female, the median age was 66 years, thirteen presented with an aortic dissection and 16 (64%) underwent concomitant procedures. These and other characteristics did not differ significantly between the groups. In-hospital mortality was statistically similar: 5 (20%) in the FET group vs. 8 (32%) for ET group (P=0.52). The incidence of stroke, acute renal failure and postoperative bleeding was comparable. The length of stay in the intensive care unit did not differ between the cohorts (P=0.258). Predictors of in-hospital mortality were length of the operation, bleeding postoperatively, and acute renal failure. The one-year survival rates were higher in the FET cohort compared to the conventional approach (60% vs. 38%), however without statistical significance. Conclusion: In regard to the short-and mid-term outcome, there were only slight differences between both techniques. In patients with extensive aneurysmal aortic disease, conventional ET and FET procedures seem to be associated with acceptable satisfactory mid-term outcome.

The Thoracic and Cardiovascular Surgeon, 2006

World Journal of Gastroenterology, 2006

The 1-and 3-year survival of all patients was 73% and 47%. In the subgroup analyses, the combinat... more The 1-and 3-year survival of all patients was 73% and 47%. In the subgroup analyses, the combination of TACE and PEI (1) was associated with a longer survival (1-, 3-, 5-year survival: 90%, 52%, and 43%) compared to PEI treatment alone (2) (1-, 3-, 5-year survival: 65%, 50%, and 37%). Secondary PEI after initial stratification to TACE (3) yielded comparable results (1-, 3-, 5-year survival: 91%, 40%, and 30%) while PEI after stratification to best supportive care (4) was associated with decreased survival (1-, 3-, 5-year survival: 50%, 23%, 12%). Apart from the chosen treatment modalities, predictors for better survival were tumor number (n < 5), tumor size (< 5 cm), no ascites before PEI, and stable serum cholinesterase after PEI (P < 0.05). The mortality within 2 wk after PEI was 2.8% (n = 3). There were 24 (8.9%) major complications after PEI including segmental liver infarction, focal liver necrosis, and liver abscess. All complications could be managed non-surgically. CONCLUSION: Repeated single-session PEI is effective in patients with advanced HCC at an acceptable and manageable complication rate. Patients stratified to a combination of TACE and PEI can expect longer survival than those stratified to repeated PEI alone. Furthermore, patients with large or multiple tumors in good clinical status may also profit from a combination of TACE and reconsideration for secondary PEI.

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2017

Zielsetzung Überprüfung der Sicherheit von perkutanen endovaskulären aortalen Prozeduren und des ... more Zielsetzung Überprüfung der Sicherheit von perkutanen endovaskulären aortalen Prozeduren und des Einflusses von Zugangscharakteristika auf Komplikationen. Material und Methoden Alle Patienten, welche sich von Januar 2010 bis Mai 2016 einer perkutanen TEVAR, EVAR und FEVAR Prozedur unterzogen haben, wurden retrospektiv ausgewertet in Bezug auf die Komplikationshäufigkeiten unter Berücksichtigung der Zugangscharakteristika wie Gefäßdurchmesser, Ausmaß vorhandener Gefäßverkalkungen, Abstand Hautoberfläche zum Zugangsgefäß sowie des Verhältnisses von Gefäßdurchmesser zum Einführbesteck. Hämostase mit oder ohne manuelle Kompression innerhalb von 15 Minuten nach Gefäßnahtverschluss wurde als primäre Hämostase definiert.

Vaskuläre Interventionen, 2017

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Herz, 2002

Aortic surgery is under continuous development. This applies to the aortic root where more and mo... more Aortic surgery is under continuous development. This applies to the aortic root where more and more reconstructive efforts are being made but also to intraoperative means of organ protection. Likewise, the endoluminar stent graft approach to downstream pathologies of the aorta has broadened the classical treatment option "replacement" by "exclusion". Some of these evolving changes in operative strategies and indications are discussed on the basis of a single-center experience.

Academic radiology, Jan 12, 2015

To determine if intraprostatic injection of gadofosveset trisodium mixed with human serum albumin... more To determine if intraprostatic injection of gadofosveset trisodium mixed with human serum albumin (HSA) can identify sentinel lymph nodes (LNs) draining the prostate on magnetic resonance imaging (MRI) in a canine model. Three male canines weighing between 25.7 and 41.3 kg were anesthetized, placed in a 3-T MRI, and a needle was placed transrectally into one side of the prostate using a commercially available intrarectal needle guide. Gadofosveset trisodium premixed with 10% HSA was then administered at doses ranging from 0.1 to 2.5 mL. T1W MRI was performed immediately after injection, and two readers evaluated images for visualization of LNs draining the prostate. Intraprostatic injection of 0.2 mL gadofosveset trisodium premixed with HSA identified the draining periprostatic LNs in all cases. Delayed images demonstrated upper echelon nodes in the pelvis and the abdomen. Higher volume injections resulted in excessive periprostatic extravasation, whereas lower volume injections res...

Kipshidze/Urgent Interventional Therapies, 2014

World Journal of Surgery, 1995

Resection remains the treatment of choice .in liver cancer. In order to avoid liver transplantati... more Resection remains the treatment of choice .in liver cancer. In order to avoid liver transplantation in conventionally unresectabie tumors ex-situ ("bench" procedure), in-situ and ante-situm resection technique should be prefered whenever feasible. Despite the deficiency of donor organs, a single center experience with 198 patients reveals that liver transplantation continues its role as a therapeutic option for selected patients. At present "favorable" indications for transplantation are International Union against Cancer (UICC)-stage II hepatocellular carcinoma as well as the subtype fibrolamellar carcinoma, uncommon tumors such as epitheloid hemangioendothelioma, hepatoblastoma, and liver metastases from neuroendocrine tumors. Due to unsatisfying resuits, intrahepatic bile duct-, stage III and IV hepatocellular carcinoma, hemangiosarcoma, and liver metastases from nonendocrine primaries should be excluded from liver transplantation alone. For these advanced tumors, especially in cases of extrahepatic involvement, a combination of liver transplantation and multivisceral resection has been proven feasible. However, a significant improvement in patient survival may only be exPected by currently investigated multimodality treatment protocols which will require further randomized studies.

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2006

Nephrology Dialysis Transplantation, 1996

Langenbeck's Archives of Surgery, 2000

Introduction: Patients with multiple aortic aneurysms represent a small subgroup with the need fo... more Introduction: Patients with multiple aortic aneurysms represent a small subgroup with the need for extensive surgical treatment at considerable risk. Endovascular treatment in combination with conventional operation is possible. We demonstrate a case with simultaneous exclusion of aneurysms of the descending thoracic and the infrarenal aorta to outline the technical obligations. Conclusion: Simultaneous exclusion of a thoracic and an abdominal aneurysm can be performed successfully by conventional infrarenal aortic replacement with bifurcat-ed dacron prosthesis and endovascular implantation of a thoracic stentgraft within one operation.

Kidney International, 1995

Minimally invasive diagnosis of renal artery stenosis by spiral computed tomography angiography. ... more Minimally invasive diagnosis of renal artery stenosis by spiral computed tomography angiography. We prospectively compared in a blinded fashion spiral computed tomography angiography (CTA) with arteriography in 62 consecutive patients with suspected renal artery stenosis (RAS). For CTA 150 ml of contrast material were injected intravenously. Arteriography was performed by DSA technique with selective catheterization of renal arteries. Of the 157 visualized renal arteries 155 could be evaluated with DSA and a total of 157 with CTA. Sensitivity of CTA for RAS 50% was 98% and the specificity was 94%. Comparison of the grade of stenosis as evaluated by DSA versus CTA showed: identical gradation in 59 arteries (DSA 50%/CTA 50%), underestimation by CTA in one artery (DSA 50 to 75%ICTA < 50%), and overestimation by CTA in six arteries (DSA < 50%/CTA 50 to 75%). Factors that may contribute to these differences include impaired renal function and possibly "underestimation" of ostial RAS by arteriography. One artery not evaluable by arteriography showed a 70% stenosis by CTA. CTA showed no major side effects. We conclude that CTA has the same accuracy for the diagnosis of RAS 50% as arteriography. However, CTA is only minimally invasive, safe, and causes less discomfort to patients. In 0.5 to 5% of patients with hypertension renal artery stenosis (RAS) is the underlying cause [1-3]. Due to its progressive nature and the high incidence of bilateral involvement (P-30%) RAS may lead to severe renal impairment and end-stage renal disease (ESRD) [4-lU]. Angioplasty or vascular surgery may cure RASinduced hypertension and prevent RAS-induced ESRD. Hence, the accurate diagnosis of RAS is of great importance [11]. Arteriography has been the gold standard for diagnosis of RAS. It is invasive, potentially dangerous, and associated with patient discomfort. To avoid these adverse effects, diagnostic vascular imaging methods have been sought that are less invasive, less expensive, and less dangerous, including intravenous digital subtraction angiography (i.v.DSA) and magnetic resonance angiography. Both methods have significant limitations. Intravenous DSA is prone to many artifacts and its overall sensitivity and specificity are not satisfactory [12, 13]. MR angiography renders reliable results only in the first three centimeters of the renal arteries [14, 15]. Computed tomography angiography (CTA) is a new, minimally invasive technique for vascular imaging that is

Journal of Vascular and Interventional Radiology, 2005

At present, a two-step surgical approach is necessary to treat patients with coexistent pathologi... more At present, a two-step surgical approach is necessary to treat patients with coexistent pathologic conditions involving the proximal and descending thoracic aorta. A hybrid endograft is described here that enables such treatment during a single operation. The Chavan-Haverich endograft consists of a Dacron vascular prosthesis with stainless-steel stents affixed at its distal end. After approval by the institutional review board, the endograft was prospectively implanted in 22 patients with multisegment thoracic aortic disease (13 men, nine women; median age, 64 years). Eleven patients had type A dissections (one acute, 10 chronic), four had a chronic type B dissection, and seven had atherosclerotic aneurysms of the ascending aorta or aortic arch as well as of the descending aorta. Of these patients, 11 additionally required aortic valve replacement or coronary artery bypass grafting. Via median sternotomy, the aortic arch was opened in circulatory arrest. After antegrade deployment of the stent-containing portion in the descending aorta, the proximal non-stent-containing endograft was used to reconstruct the aortic arch. Median follow-up was 14 months. Endograft implantation was successful in all but one patient. Complications included neurologic deficits that were transient in one case and lasting in two, two cases of vocal cord paralysis, and one death. In all patients with atherosclerotic aneurysms who received the endograft (six of seven), aneurysm thrombosis was noted at follow-up. In aortic dissections, partial or complete false-lumen thrombosis to the level of the stents occurred in all patients. None of the patients showed a progressive widening of the descending aorta. The Chavan-Haverich endograft enables one-step treatment of multisegment pathologic conditions affecting the thoracic aorta that otherwise would require two or more operations.

Journal of Endovascular Therapy, 2007

To report a novel complication of a hybrid &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;a... more To report a novel complication of a hybrid &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;frozen elephant trunk&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; endograft used in the treatment of a multisegmentally diseased aorta. A 53-year-old man with chronic type A aortic dissection and previous replacement of the supracoronary ascending aorta underwent a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;frozen elephant trunk&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; procedure using a hybrid endograft. The stent-graft was placed deep in the descending aorta to cover the multiple distal re-entries. Due to ineffective covering of the re-entries, a patent false lumen led to rapid repressurization of the false lumen immediately distal to the circumferential elephant trunk anastomosis. Compression of the non-stented portion of the hybrid endograft caused a functional aortic stenosis, with severe hemodynamic consequences. Endovascular treatment of the compression by retrograde transfemoral placement of a stent-graft in the non-stented portion of the hybrid endograft achieved free flow in the distal aorta. This case documents a new complication of the frozen elephant trunk procedure; a pseudocoarctation from a repressurized proximal false lumen was successfully managed with a stent-graft to support the non-stented segment of the hybrid endograft.

Journal of Endovascular Therapy, 2010

To describe the use of a hybrid frozen elephant trunk technique to treat a patient suffering from... more To describe the use of a hybrid frozen elephant trunk technique to treat a patient suffering from a multisegmentally diseased, dextropositioned aortic arch and right descending aorta. The technique is illustrated in a 58-year-old woman who was diagnosed with chronic type A aortic dissection in a right aortic arch and descending aorta; a lusoric left subclavian artery passed behind the esophagus. Aneurysmal dilatation of the arch and descending aorta required treatment. A frozen elephant trunk procedure was performed in a single stage via a median sternotomy using a hybrid Chavan-Haverich endograft, with complete surgical replacement of aortic arch. The stents for the endograft were placed in the descending aorta in an antegrade fashion through the opened aortic arch. This case demonstrates the feasibility of treating complex pathologies of the thoracic aorta even in cases of aberrant anatomy. A conventional 2-stage approach for treatment of the complex pathology could have been complicated due to difficulties with exposure.