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Dive into the research topics where Andrew Kwak is active.

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Featured researches published by Andrew Kwak.


The Journal of Thoracic and Cardiovascular Surgery | 2010

Nonoperative thoracic duct embolization for traumatic thoracic duct leak: Experience in 109 patients

Maxim Itkin; John C. Kucharczuk; Andrew Kwak; Scott O. Trerotola; Larry R. Kaiser

OBJECTIVE To demonstrate the efficacy of a minimally invasive, nonoperative, catheter-based approach to the treatment of traumatic chyle leak. METHODS A retrospective review of 109 patients was conducted to assess the efficacy of thoracic duct embolization or interruption for the treatment of high-output chyle leak caused by injury to the thoracic duct. RESULTS A total of 106 patients presented with chylothorax, 1 patient presented with chylopericardium, and 2 patients presented with cervical lymphocele. Twenty patients (18%) had previous failed thoracic duct ligation. In 108 of 109 patients, a lymphangiogram was successful. Catheterization of the thoracic duct was achieved in 73 patients (67%). In 71 of these 73 patients, embolization of the thoracic duct was performed. Endovascular coils or liquid embolic agent was used to occlude the thoracic duct. In 18 of 33 cases of unsuccessful catheterization, thoracic duct needle interruption was attempted below the diaphragm. Resolution of the chyle leak was observed in 64 of 71 patients (90%) post-embolization. Needle interruption of the thoracic duct was successful in 13 of 18 patients (72%). In 17 of the 20 patients who had previous attempts at thoracic duct ligation, embolization or interruption was attempted and successful in 15 (88%). The overall success rate for the entire series was 71% (77/109). There were 3 (3%) minor complications. CONCLUSION Catheter embolization or needle interruption of the thoracic duct is safe, feasible, and successful in eliminating a high-output chyle leak in the majority (71%) of patients. This minimally invasive, although technically challenging, procedure should be the initial approach for the treatment of a traumatic chylothorax.


Journal of Vascular and Interventional Radiology | 2004

Relationship between Chest Port Catheter Tip Position and Port Malfunction after Interventional Radiologic Placement

Jakob C.L. Schutz; Aalpen A. Patel; Timothy W.I. Clark; Jeffrey A. Solomon; David B. Freiman; Catherine M. Tuite; Jeffrey I. Mondschein; Michael C. Soulen; Richard D. Shlansky-Goldberg; S. William Stavropoulos; Andrew Kwak; Jesse Chittams; Scott O. Trerotola

PURPOSE The relationship between catheter tip position of implanted subcutaneous chest ports and subsequent port malfunction was investigated. Tip movement from initial supine position to subsequent erect position was also evaluated. MATERIALS AND METHODS Patients who underwent imaging-guided internal jugular chest port placement between July 2001 and May 2003 were identified with use of a quality-assurance database. Sixty-two patients were included in the study (22 men and 40 women), with a mean age of 58 years (range, 27-81 years). Catheter tip location on the intraprocedural chest radiograph was determined with use of two methods. First, the distance from the right tracheobronchial angle (TBA) was recorded (TBA distance). Second, tip location was classified into six anatomic regions: 1, internal jugular veins; 2, brachiocephalic veins; 3, superior vena cava (SVC; n = 11); 4, SVC/right atrial junction (n = 22); 5, upper half of right atrium (n = 25); and 6, lower half of right atrium (n = 4). For the duration of follow-up, catheter tip location was documented, as were all episodes of catheter malfunction. RESULTS Patients with catheter tips initially placed in position 3 had a higher risk of port malfunction (four of 11; 36%) than patients with catheter tips located in position 5 (two of 25; 8%). This difference narrowly fell short of statistical significance (P =.057). When comparing intraprocedural chest radiographs to the first erect chest radiographs, significant upward tip movement was noted. The tips migrated cephalad an average of 20 mm (P =.003) and 1.0 position units (P =.001). DISCUSSION Catheter tips placed in the SVC tended to have a greater risk of port malfunction compared with those positioned in the right atrium. Chest ports migrated cephalad between the supine and erect positions.


Journal of Vascular and Interventional Radiology | 2006

Single-center Experience with the Arrow-Trerotola Percutaneous Thrombectomy Device in the Management of Thrombosed Native Dialysis Fistulas

Josh B. Shatsky; Jeffrey S. Berns; Timothy W.I. Clark; Andrew Kwak; Catherine M. Tuite; Richard D. Shlansky-Goldberg; Jeffrey I. Mondschein; Aalpen A. Patel; S. William Stavropoulos; Michael C. Soulen; Jeffrey A. Solomon; Sidney Kobrin; Jesse Chittams; Scott O. Trerotola

PURPOSE The present study sought to evaluate the performance of the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) in the treatment of native fistula thrombosis in a U. S. hemodialysis population. Specifically, the technical success, clinical success, complication rate and type, primary and secondary patency rates, effect of adjunctive thrombolytic therapy, and any variables that affected outcomes of procedures in which this device was used were analyzed. MATERIALS AND METHODS Forty-two patients with 44 thrombosed native fistulas (17 radiocephalic, 10 brachiocephalic, 10 transposed or superficialized, five graft/fistula hybrids, and two leg fistulas) were treated with 62 mechanical thrombolysis procedures with use of the PTD. All patients had large clot burden. The device type was recorded in 43 procedures: standard (n = 21), over-the-wire (OTW; n = 19), or both (n = 3). No device was used in two cases because of inability to cross the anastomosis. Adjunctive therapies (n = 18) included the use of tissue plasminogen activator (tPA; n = 16) and deployment of the AngioJet device with (n = 1) or without tPA (n = 1). Stents were inserted in four procedures. Outcome variables included technical and clinical success, complications, and primary and secondary patency. Cox proportional-hazards regression and Kaplan-Meier analyses were performed. RESULTS The technical success rate was 87% (54 of 62) and the clinical success rate was 79% (49 of 62). Percutaneous transluminal angioplasty was performed in all but two procedures. Complications occurred in 13% of procedures (n = 8); three resulted in technical failure. The primary patency rates were 38% at 6 months and 18% at 12 months; secondary patency rates were 74% and 69%, respectively. Outcomes were not affected by adjunctive techniques, fistula type, age of fistula, device type (ie, OTW vs standard), or patient sex. Secondary patency was superior when no residual clot or stenosis was present (P = .003). CONCLUSIONS The PTD is effective for percutaneous treatment of thrombosed hemodialysis fistulas, with good short- and long-term outcomes in a U.S. population. Within the limitations of a retrospective study with a small sample size, use of an adjunctive thrombolytic agent did not appear to improve results compared with the use of the device alone.


Journal of Vascular and Interventional Radiology | 2006

Role of Ultrasound Surveillance of Transjugular Intrahepatic Portosystemic Shunts in the Covered Stent Era

Caitlin E. Carr; Catherine M. Tuite; Michael C. Soulen; Richard D. Shlansky-Goldberg; Timothy W.I. Clark; Jeffrey I. Mondschein; Andrew Kwak; Aalpen A. Patel; Beverly G. Coleman; Scott O. Trerotola

PURPOSE To assess ultrasound (US) surveillance of expanded polytetrafluoroethylene (ePTFE)-covered stents in transjugular intrahepatic portosystemic shunts (TIPS). MATERIALS AND METHODS Procedural data, including stent size and portosystemic gradients (PSG) before and after creation of TIPS, were obtained retrospectively in 55 patients (33 men, 22 women). Chart review provided clinical information, including etiology of liver disease, indication for TIPS creation, and Child-Pugh class. Radiology reports provided US venography data and pathology reports confirmed shunt status in transplant recipients. Patients had baseline US examinations 3-7 days after TIPS creation with scheduled follow-up at 1, 3, 6, and 12 months after the procedure. Clinical and radiology reports were compared to evaluate US surveillance of Viatorr stents. RESULTS One hundred fifty-nine US examinations were performed on 52 patients, for an average 3.1 studies per patient (range, 1-7) over a mean follow-up duration of 173 days (range, 0-1,013 d). Sixty-four US studies (40%) were baseline studies, 88 studies (55%) were routine follow-up studies, and seven (4%) were interval studies. US predicted TIPS abnormalities in 30 of 159 studies (19%); venography followed 15 of 30 abnormal US findings (50%) and clinical examinations complemented 10 of 15 venograms (67%). Venography and US were concordant in eight of 15 paired studies (53%); clinical examinations, when conducted, accurately predicted shunt status in all but one case. US findings changed management in six of 159 studies (4%): five of six (83%) were baseline evaluations and the other one (17%) was a routine follow-up examination. A total of five baseline US examinations (8%) and one surveillance examination (1%) altered patient management. CONCLUSIONS A single US examination after a TIPS procedure to confirm immediate function may be valuable, but routine US is not effective for long-term surveillance of ePTFE-covered stents.


Journal of Vascular and Interventional Radiology | 2008

Large or Small Bore, Push or Pull: A Comparison of Three Classes of Percutaneous Fluoroscopic Gastrostomy Catheters

Yuo-Chen Kuo; Richard D. Shlansky-Goldberg; Jeffrey I. Mondschein; S. William Stavropoulos; Aalpen A. Patel; Jeffrey A. Solomon; Michael C. Soulen; Andrew Kwak; Maxim Itkin; Jesse Chittams; Scott O. Trerotola

PURPOSE To compare the tube performance and complication rates of small-bore, large-bore push-type, and large-bore pull-type gastrostomy catheters. MATERIALS AND METHODS A total of 160 patients (74 men, 86 women; mean age, 66.9 years, range, 22-95 y) underwent percutaneous fluoroscopic gastrostomy placement between January 2004 and March 2006. Choice of catheter was based on the preference of the attending radiologist. Data were collected retrospectively with institutional review board approval. Radiology reports provided information on the catheter, indication for gastrostomy, technical success, and immediate outcome. Chart review provided data on medical history, postprocedural complications, progress to feeding goal, and clinical outcomes. Statistical analysis was performed to compare the three classes of gastrostomy catheters. RESULTS All 160 catheters were placed successfully. Patients who received small-bore catheters (14 F; n = 88) had significantly more tube complications (17% vs 5.6%) and were less likely to meet their feeding goal (P = .035) compared with patients with large-bore catheters (20 F; n = 72). No difference was observed in terms of major or minor complications. Large-bore push-type (n = 14) and pull-type catheters (n = 58) were similar in terms of complication rates. Patients who received large-bore push-type catheters achieved their feeding goals in significantly less time than those with large-bore pull-type catheters (average, 3.8 days vs 6.0 days; P = .04). CONCLUSIONS Patients who received small-bore gastrostomy catheters are significantly more prone to tube dysfunction. Large-bore catheters should be preferentially used, with push-type catheters performing better with regard to the time to achieve feeding goal.


Journal of Vascular and Interventional Radiology | 2009

Incidence and management of percutaneous transluminal angioplasty-induced venous rupture in the "fistula first" era.

Zev Noah Kornfield; Andrew Kwak; Michael C. Soulen; Aalpen A. Patel; Sidney Kobrin; Raphael M. Cohen; Mark Mantell; Jesse Chittams; Scott O. Trerotola

PURPOSE Percutaneous transluminal angioplasty (PTA)-induced venous rupture is a common complication of hemodialysis access interventions. The authors sought to determine if venous rupture rates and management differed between grafts and fistulas, and in the fistula subset, between transposed and nontransposed fistulas. MATERIALS AND METHODS Patients experiencing venous rupture during hemodialysis PTA over a 5-year period were identified. Of 1,985 hemodialysis interventions, 75 ruptures occurred in 69 patients (46 women) with a mean age of 63 years (range, 31-88 y). Rupture rates, proportion of successful treatments, and treatment type and number (ie, balloon tamponade, stent, covered stent) were determined. RESULTS Rupture was more common in fistulas overall (5.6%, 39 of 693) compared with grafts (2.8%, 36 of 1,292; P = .002), in transposed (10.7%, 20 of 187) compared with nontransposed fistulas (3.8%, 19 of 506; P = .001), and in transposed fistulas compared with grafts (P = .0001). There was no significant difference between nontransposed fistulas and grafts. Treatment success (ie, resolution of extravasation) was the same among groups: 69% (27 of 39) in fistulas overall, 70% (14 of 20) in transposed fistulas, 68% (13 of 19) in nontransposed fistulas, and 72% (26 of 36) in grafts. There was a greater need for stents in grafts (38.9%, 14 of 36) compared with fistulas (12.8%, five of 39; P = .003). CONCLUSIONS PTA-induced rupture is more common in fistulas than grafts, and this effect seems nearly entirely driven by transposed fistulas. Although rupture treatment in fistulas of all types yielded similar success to grafts, and graft ruptures were more difficult to treat than fistula ruptures, the high rupture rates in transposed fistulas attest to the increased difficulty of treating this subset of fistulas.


Journal of Vascular and Interventional Radiology | 2009

Angiographic changes following the use of a purse-string suture hemostasis device in hemodialysis access interventions.

Timothy W.I. Clark; Shawn Haji-Momenian; Andrew Kwak; Michael C. Soulen; S. William Stavropoulos; Maxim Itkin; Aalpen A. Patel; Jeffrey I. Mondschein; Scott O. Trerotola

PURPOSE To evaluate late angiographic changes at the puncture site with use of a suture lock device for hemostasis after hemodialysis access interventions. MATERIALS AND METHODS Thirty-five patients who underwent percutaneous intervention of a failing or thrombosed access had 76 puncture sites (58 grafts, 15 fistulas, three composite) managed with a purse-string suture lock device. All patients had follow-up fistulograms available for analysis. Fistulograms at the site of sheath insertion were retrospectively compared with those obtained during subsequent hemodialysis access procedures to assess for changes in access lumen diameter. Access type, sheath size, and heparin dose were examined as predictors of access diameter change at the puncture site. RESULTS The mean time to follow-up fistulography was 4.7 months; the cumulative observation time of the patient cohort was 30.5 dialysis years. The mean change in access diameter at the previous puncture site was -0.3%. No puncture sites became aneurysmal or stenotic during follow-up. Two of the 76 puncture sites (both grafts) developed mild (+28%) and moderate (+43%) bulging at the sheath site. The remaining 74 puncture sites (97%) showed no significant change in access diameter. The mean change in access diameter among fistulas was -6.2%, and that among grafts was +1.5% (P = .06). Neither sheath size (P = .26) nor heparin dose (P = .48) had an effect on access diameter. CONCLUSIONS No patients developed aneurysms or stenosis at the puncture site after use of a suture lock device for hemostasis. This technique is consistent, safe, and effective in obtaining hemostasis after dialysis access interventions of fistulas and grafts.


Radiology | 2006

Asymptomatic Central Venous Stenosis in Hemodialysis Patients

Rebecca D. Levit; Raphael M. Cohen; Andrew Kwak; Richard D. Shlansky-Goldberg; Timothy W.I. Clark; Aalpen A. Patel; S. William Stavropoulos; Jeffrey I. Mondschein; Jeffrey A. Solomon; Catherine M. Tuite; Scott O. Trerotola


Radiology | 2007

Salvage of Nonmaturing Native Fistulas by Using Angioplasty

Timothy W.I. Clark; Raphael A. Cohen; Andrew Kwak; James F. Markmann; S. William Stavropoulos; Aalpen A. Patel; Michael C. Soulen; Jeffrey I. Mondschein; Sidney Kobrin; Richard D. Shlansky-Goldberg; Scott O. Trerotola


Journal of Vascular and Interventional Radiology | 2005

Prospective Study of Balloon Inflation Pressures and Other Technical Aspects of Hemodialysis Access Angioplasty

Scott O. Trerotola; Andrew Kwak; Timothy W.I. Clark; Jeffrey I. Mondschein; Aalpen A. Patel; Michael C. Soulen; S. William Stavropoulos; Richard D. Shlansky-Goldberg; Jeffrey A. Solomon; Catherine M. Tuite; Jesse Chittams

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Aalpen A. Patel

University of Pennsylvania

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Michael C. Soulen

University of Pennsylvania

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Maxim Itkin

Hospital of the University of Pennsylvania

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