Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Vairavan S. Subramanian is active.

Publication


Featured researches published by Vairavan S. Subramanian.


Urology | 2009

Utility of preoperative renal artery embolization for management of renal tumors with inferior vena caval thrombi.

Vairavan S. Subramanian; Andrew J. Stephenson; David A. Goldfarb; Amr Fergany; Andrew C. Novick; Venkatesh Krishnamurthi

OBJECTIVES To review our experience with radical nephrectomy and inferior vena cava thrombectomy (RNIVCT) to determine the utility of preoperative embolization. Preoperative embolization has been used as an adjunctive procedure to facilitate surgical resection of complex renal tumors. METHODS From 1990 to 2007, 225 patients with renal tumors and inferior vena cava thrombus underwent RNIVCT, including 135 patients who had undergone preoperative renal artery embolization and 90 patients who had not. The effect of embolization on perioperative morbidity and mortality, transfusion requirements, blood loss, and operative time was analyzed by comparing the 2 groups. RESULTS The mean primary tumor size was similar in both groups; however, 67% of the RNIVCT embolization group vs 48% of the nonembolization group had retrohepatic (level III) or supradiaphragmatic (level IV) thrombus extension (P = .032). The RNIVCT embolization patients had a greater median number of perioperative units transfused (8 vs 4; P = .001), a longer operative time (390 vs 313 minutes; P < .001), more postoperative complications (43% vs 29%; P < .001), a longer intensive care unit stay (2 vs 0.5 days), and increased perioperative mortality (13% vs 3%; P = .017). No differences were found in intraoperative complications or length of hospitalization. Multivariate analysis showed a fivefold greater risk of perioperative death (adjusted odds ratio 5.5; P = .029) and a trend toward increased blood transfusion (regression coefficient 3.9; P = .08) with preoperative embolization. CONCLUSIONS The results of our study have shown that routine preoperative renal artery embolization in patients undergoing RNIVCT does not provide any measurable benefit in reducing blood loss or complications and was associated with increased major perioperative complications and mortality.


Urologic Oncology-seminars and Original Investigations | 2010

Complications of open primary and post-chemotherapy retroperitoneal lymph node dissection for testicular cancer.

Vairavan S. Subramanian; Carvell T. Nguyen; Andrew J. Stephenson; Eric A. Klein

OBJECTIVE Treatment decisions regarding the use of retroperitoneal lymph node dissection (RPLND) for low-stage and advanced testicular cancer may be influenced by the morbidity of the procedure. We sought to compare the complication profile of primary (P-) and post-chemotherapy (PC-) RPLND using a standardized complication grading scale. MATERIALS AND METHODS A retrospective analysis was conducted of 112 and 96 patients who underwent P-RPLND and PC-RPLND, respectively, between 1982 and 2007 for perioperative outcomes and late complications. Postoperative complications were graded using a 5-tiered scale based on the severity and/or level of intervention required for resolution. RESULTS P-RPLND patients had rates of 5%, 24%, and 7% for intraoperative, postoperative, and late complications, respectively. For PC-RPLND, these rates were 12%, 32%, and 7%, respectively (P = 0.11, 0.19, and 1, respectively). Major postoperative complications (grades III-V) were observed in 3 (3%) P-RPLND and 8 (8%) PC-RPLND patients (P = 0.15), including 1 fatal pulmonary embolus in a PC-RPLND patient. Ileus accounted for 63% and 45% of postoperative complications of P-RPLND and PC-RPLND, respectively. PC-RPLND was associated with significantly greater operative times, blood loss, and transfusion rates (P < 0.001). Compared with PC-RPLND after first-line chemotherapy for advanced NSGCT, there were no significant differences in perioperative outcomes for PC-RPLND performed in other settings. CONCLUSIONS P-RPLND and PC-RPLND are associated with low rates of serious short- and long-term complications and negligible mortality, without significant differences between the 2 procedures. The safe morbidity profile of RPLND performed by fellowship-trained urologic oncologists should be considered during treatment decision-making for low-stage and advanced testicular cancer.


Urology | 2011

Acute kidney injury: novel biomarkers and potential utility for patient care in urology.

Anil A. Thomas; Sevag Demirjian; Brian R. Lane; Matthew N. Simmons; David A. Goldfarb; Vairavan S. Subramanian; Steven C. Campbell

Urologists are integrally involved in the management of acute kidney injury (AKI), which is common after renal surgery or secondary to postrenal (obstructive) etiologies. The measurement of serum creatinine is a suboptimal indicator of AKI because it lags behind acute changes in renal function. Recent advances indicate that serum/urine biomarkers will prove useful for early detection of AKI, analogous to the use of cardiac enzymes for acute myocardial infarction. These serum/urine markers may guide future therapy, facilitate research efforts to reduce the severity of AKI, such as after partial nephrectomy, and allow for more accurate prognostication for patients with AKI.


The Journal of Urology | 2010

α-Melanocyte Stimulating Hormone Analogue AP214 Protects Against Ischemia Induced Acute Kidney Injury in a Porcine Surgical Model

Matthew N. Simmons; Vairavan S. Subramanian; Sebastien Crouzet; Georges Pascal Haber; José Roberto Colombo; Osamu Ukimura; Søren Neilsen; Inderbir S. Gill

PURPOSE alpha-Melanocyte stimulating hormone protects kidneys against ischemia and sepsis induced acute kidney injury in rodents. We examined the efficacy of alpha-melanocyte stimulating hormone analogue AP214 to protect against acute kidney injury in higher vertebrates. MATERIALS AND METHODS We performed a prospective, blinded, randomized, placebo controlled study in 26 pigs. Laparoscopic technique was used for left nephrectomy and to induce complete warm ischemia in the right kidney for 120 minutes. AP214 (200 microg/kg intravenously) was administered daily on the day of surgery and for 5 days thereafter. Kidney function was measured for 9 days. We measured changes in serum creatinine, estimated glomerular filtration rate, serum C-reactive protein and urine interleukin-18. RESULTS In the placebo control and AP214 groups mean peak serum creatinine was 10.2 vs 3.92 mg/dl and the estimated glomerular filtration rate nadir was 22.9 vs 62.6 ml per minute per kg (each p = 0.001). Functional nadir occurred at 72 vs 24 hours in the control vs AP214 groups. Estimated glomerular filtration rate outcome on postoperative day 9 was 118 vs 156 ml per minute per kg in the control vs AP214 groups (p = 0.04). CONCLUSIONS We noted a robust renoprotective effect of AP214. A similar AP214 effect may be observed in humans. Future research includes mechanistic studies in pigs and a phase II human clinical trial of AP214 in kidney transplant and partial nephrectomy populations.


Urology | 2008

Right-sided intrathoracic renal ectopia with Bochdalek's hernia.

Vairavan S. Subramanian; David A. Goldfarb

A 23-year-old woman was evaluated for right flank pain of one year duration. Magnetic resonance imaging (MRI) revealed a 6 cm defect in the right hemidiaphragm with herniation of the right kidney, adrenal gland, and posterior right hepatic lobe consistent with a congenital right Bochdalek hernia. Computed tomography (CT) urogram confirmed lack of masses, hydronephrosis, and renal calculi and defined vascular and ureteral anatomy through the diaphragmatic hernia. Intrathoracic kidney is rare and is usually discovered incidentally. In the absence of other renal pathology it requires no surgical intervention.


The Journal of Urology | 2008

LAPAROSCOPIC PYELOLITHOTOMY IN A PELVIC KIDNEY

Angelo A. Baccala; Vairavan S. Subramanian; Marcelo Miranda; Mihir M. Desai

orientation of the renal pelvises and the location of the calculus often prevents percutaneous access. However, we show that by keeping a few key principles in mind, laparoscopic surgical success can be achieved in such situations. METHODS: We performed a left laparoscopic pyelolithotomy in a 33 year old woman with a 5cm staghorn calculus. The patient had no evidence of ureteral pelvic junction (UPJ) obstruction on mag-3 renal scan. A retrograde was performed and a 7 fr. double J stent was placed prior to the procedure. Port placement was performed with 4 ports placed in a diamond shape below the umbilicus. The ureter and renal pelvis


Nature Clinical Practice Urology | 2008

A case of spermatic cord teratoma in low-stage testicular cancer managed by surveillance

Vairavan S. Subramanian; Timothy Gilligan; Eric A. Klein

Background A 25-year-old male presented to his local urologist with new-onset right testicular pain and swelling detected on self examination. A scrotal ultrasound scan showed a right testicular mass, suspicious for neoplasm. Serum levels of α-fetoprotein and human chorionic gonadotropin were found to be elevated at 920.2 µg/l and 637.4 U/l, respectively. The patient underwent right inguinal orchiectomy and was diagnosed with nonseminomatous germ cell tumor of the right testis, composed of yolk sac tumor, teratoma, and embryonal carcinoma with no evidence of metastatic disease. He opted to remain under surveillance rather than undergo primary chemotherapy or retroperitoneal lymph node dissection for his clinical stage I disease. Serologic relapse at 4 months after orchiectomy was successfully treated with bleomycin, etoposide and cisplatin (BEP) chemotherapy.Investigations Surveillance comprised regular clinic visits, measurement of serum levels of α-fetoprotein, human chorionic gonadotropin and lactate dehydrogenase, chest X-ray and CT of the abdomen and pelvis. Pathology of the testicular mass was reviewed.Diagnosis A 1.7 cm nodule anterior to the right psoas muscle suspicious for metastatic disease that was seen on CT 16 months after orchiectomy was pathologically confirmed as recurrent mature teratoma in the spermatic cord. Additionally, one of eleven interaortocaval lymph nodes showed evidence of teratoma.Management Bilateral nerve-sparing retroperitoneal lymph node dissection with complete excision of the right spermatic cord was performed. The patient has since remained disease-free, with normal levels of serum tumor markers and no evidence of metastasis on chest X-ray and abdominal CT.


Urology | 2011

MP-06.11 Contemporary Vascular Bypass Approach for Treatment of Retroperitoneal Tumors with Inferior Vena Cava and Atrial Extension: A 20-Year Single Institution Experience

Venkatesh Krishnamurthi; Vairavan S. Subramanian; Ryan K. Berglund; Jose L. Navia; E. Nowicki; Ranko Miocinovic; Andrew J. Stephenson; David A. Goldfarb; Eric A. Klein; Andrew C. Novick


The Journal of Urology | 2008

PRIMARY VS. POSTCHEMOTHERAPY RETROPERITONEAL LYMPH NODE DISSECTION FOR GERM CELL AND TESTICULAR CANCER: INTRA- AND POSTOPERATIVE COMPLICATIONS

Vairavan S. Subramanian; Carvell T. Nguyen; Andrew J. Stephenson; Eric A. Klein


The Journal of Urology | 2008

POST-CHEMOTHERAPY RETROPERITONEAL LYMPH NODE DISSECTION CAN NOT BE SAFELY OMITTED IN PATIENTS WITH METASTATIC NON-SEMINOMATOUS GERM CELL TESTIS CANCER

Carvell T. Nguyen; Vairavan S. Subramanian; Andrew J. Stephenson; Eric A. Klein

Collaboration


Dive into the Vairavan S. Subramanian's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge