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S S Ahn

Publications and source records attributed to S S Ahn.

At least 19 recordsLinked to original sources
PubMed2004

A preclinical cadaver fitting study of implantable biventricular assist device-- AnyHeart.

A multifunctional, Korean-made artificial heart (AnyHeart) was developed, and prior to its clinical application, a cadaver-fitting study was performed. The study proposed to determine the optimal cannulation approach, implantation technique and route of the cannula to minimize the organ compression of AnyHeart. The anatomical feasibility and a variety of surgical techniques were evaluated using ten preserved, human cadavers. Implanting AnyHeart with ease is possible using various approaches, including a median sternotomy, and a right or left lateral thoracotomy. The lateral thoracotomy approach is shown to be safe and reproducible, especially in patients who have already undergone an operation that used a median sternotomy. The results of this study will guide improvements in the designs of cannulae and AnyHeart for future clinical applications.

Adolescent↗
PubMed2003

Applications of the pulsatile flow versatile ECLS: in vivo studies.

INTRODUCTION: T-PLS (Twin-Pulse Life Support) is the first commercial pulsatile ECLS (Extra Corporeal Life Support) device (1). The dual sac structure of T-PLS can effectively reduce high membrane oxygenator inlet pressure and hemolysis. To verify both the use of T-PLS for ECLS and the advantages of T-PLS, we tested various models. METHOD AND RESULTS: In the partial CPB (cardio pulmonary bypass) model (swine), T-PLS (N = 6), and Biopump (N = 2), a single pulsatile pump (N = 2), were compared. In the case of single pulsatile flow, during pump systole, pressure increased to 700 - 800 mmHg at the inlet port of the membrane oxygenator. fHb, a hemolysis measurement value, was about 80 mg/dL at 3 hours. On the contrary, because of T-PLS's dual sac system, the pressure of T-PLS had a maximum value of about 250 mmHg and fHb was similar to that of the commercial centrifugal pumps. In the total CPB model (bovine, N = 6), the heart was stopped via cardioplegia (Kcl). T-PLS flow was maintained at 3.0-4.5 L/min. T-PLS functioned like a natural heart, having a pulse pressure of 26-43 mmHg and a pulse rate of 40-60 bpm (beats per minute). In the emergency case model (canine, N = 6), T-PLS was started 10 minutes after cardiac arrest from electronic shock. In spite of cardiac arrest for a period of 40 minutes, the heart was recovered after defibrillation. In the ARDS (Acute Respiratory Distress Syndrome) model (canine, N = 6), minimal ventilator parameters were set: tidal volume 130 ml, respiration rate = bpm, FiO2 = 10%. Three hours after starting T-PLS, PO2 of the carotid artery blood (after 2 hours: 195 +/- 89.4; after 3 hours: 258 +/- 99.3 mmHg) was above half the value of the femoral artery but was within normal range. CONCLUSION: It is suggested that a portable pulsatile ECLS like T-PLS may be used as a CPB device and as an alternative CPR (cardiopulmonary resuscitation) device in the case of cardiac arrest. Due to the pulsatile flow, oxygenated blood is delivered to the patient without overloading the ARDS patients heart.

Animals↗
PubMed2001

Safety and efficacy of early surgical decompression of the thoracic outlet for Paget-Schroetter syndrome.

The surgical treatment of Paget-Schroetter syndrome has evolved to include early thrombolytic therapy and an interval period of anticoagulation, followed by late surgical decompression of the thoracic outlet. More recently, we have developed an abbreviated course of therapy in which the thrombolytic therapy is followed by early surgical decompression during the same admission, then a period of anticoagulation. We compared early surgical decompression with the standard management protocol to determine safety and efficacy of the early treatment algorithm. Nine patients were treated with lysis and early operation. These were compared with the preceding nine consecutive patients treated with lysis and staged operation. Demographic data, risk factors, duration of thrombosis, lytic therapy, time to surgery, operative variables, and postoperative complications were analyzed. Our results showed that thrombolysis followed by early operation does not result in increased perioperative morbidity or mortality. Early surgical decompression of the thoracic outlet during the same admission as lysis is as safe and efficacious as the traditional (staged decompression) approach to Paget-Schroetter syndrome. Lysis followed by early surgical decompression should be considered a new standard of care in the management of Paget-Schroetter syndrome.

Adult↗
PubMed2001

Current training and practice of endovascular surgery: a survey.

Endovascular surgery (EVS) has become of great interest to the vascular community. However, little data exist about the current status of training and utilization of EVS, thus prompting this survey. During a national vascular meeting, all participants (n = 132) filled out a 2-page questionnaire. Respondents (mean age 39 years, 87% male) were 68 vascular surgeons in practice (52%), and 64 fellows (48%), representing a significant fraction of trainees in North America. Practice location included university hospital (39%), private hospital/clinic (52%), and government hospital (8%). According to respondents, in their respective communities, most of the EVS was performed by radiologists (66%), followed by vascular surgeons (19%), cardiologists (13%), and vascular medicine physicians (2%). A majority of respondents (75%) currently perform EVS; surgeons in practice < 3 years had the highest rate (90%). Utilization rates among the nine interventions surveyed ranged from angiography (72%) and angioplasty (65%) to intravascular ultrasound (IVUS) (21%) and atherectomy (12%). Procedure totals showed that approximately 20% of fellows performed > 100 angiograms and 10% performed > 25 endovascular grafts/year, whereas nonfellows performed few of the latter. Most of the EVS (72%) was performed in the operating room with portable imaging equipment and EVS accounted for 14% of all vascular procedures. Most respondents (86%) believed that EVS would become a major component of vascular surgery and comprise 30% of their future practice. Seventy-six percent thought their training was insufficient and 85% said they would devote 3 months or less for further endovascular training. In conclusion, a vast majority of vascular trainees and surgeons are performing EVS, however, individual caseloads vary greatly. The belief that endovascular surgery will play an increasing role in vascular surgery practice is strong and interest in further training of short duration is widespread. Broader-based data collection and longitudinal studies on this issue are warranted.

Adult↗
PubMed2001

Combined carotid endarterectomy and coronary bypass: a decade experience at UCLA.

PURPOSE: The purpose of this review was to determine outcomes for combined carotid endarterectomy (CEA) and coronary revascularization (CABG) in patients with asymptomatic carotid stenosis. METHODS: We reviewed the medical records of consecutive combined procedures (CEA and CABG), performed at UCLA Medical Center from October, 1989 to January, 1999. FINDINGS: There were 43 patients, 27 men and 16 women, with a mean age of 71 yr (range 51-87). Thirty-four patients 79% (34/43) had asymptomatic carotid stenosis. Stroke occurred in three patients (3/43 = 6.9%). Stroke ipsilateral to the CEA occurred in two patients: one asymptomatic (1/34 = 2.9%) and one symptomatic (1/9 = 11.1%). CONCLUSIONS: The majority of patients undergoing combined CEA/CABG have asymptomatic carotid stenosis identified in preparation for elective CABG. The asymptomatic carotid subset stroke rate of 2.9% resulting from a combined CEA/CABG is higher than our reported rate for CEA performed alone. In patients with asymptomatic carotid stenosis, the combined procedure should be selectively performed.

Aged↗
PubMed2001

Carotid endarterectomy with normal findings from a completion study: Is there need for early duplex scan?

OBJECTIVE: The objective of this study was to determine the value of early (< 6 months) duplex scanning after carotid endarterectomy (CEA) with an intraoperative completion study with normal results. Attention was paid to restenosis rates and reoperation for recurrent stenosis within the first 6 months. METHODS: A retrospective review was performed on 380 CEAs (338 patients) with intraoperative completion studies and duplex surveillance within the first 6 months. Results of completion studies, restenosis rates, and recurrent symptoms were evaluated for each operation. Studies were performed from 0 to 200 days postoperatively (median, 28). RESULTS: Intraoperative completion studies included 333 angiograms, 26 duplex scans, and 21 angiograms with duplex scans. Of the 380 intraoperative completion studies, 28 (7.5%) had abnormal findings, including 14 abnormal internal carotid arteries (ICAs). Twenty-four procedures were revised, and the findings of all repeat completion studies were normal. Of the initial completion studies, in four cases, abnormalities (3 ICAs) were insignificant and did not warrant further intervention. Follow-up ICA duplex scans had normal results after 364 (95.8%) CEAs. There were 14 mild recurrent ICA stenoses and two moderate recurrent ICA stenoses; neither had abnormal findings from the completion study. There were no severe recurrent ICA stenoses. External carotid artery (ECA) recurrent stenosis included 7 mild, 15 moderate, and 9 severe restenoses. CONCLUSIONS: Only 0.5% of CEAs developed moderate restenosis. No procedures had severe recurrent stenosis on duplex scan within the first 6 months, and none required intervention. Duplex surveillance in the first 6 months is relatively unproductive, providing that there were normal results from an intraoperative completion study for each patient. Routine surveillance can be started at 1 year.

Adult↗
PubMed2000

Selective botulinum chemodenervation of the scalene muscles for treatment of neurogenic thoracic outlet syndrome.

Patients with thoracic outlet syndrome (TOS) who improve temporarily after anesthetic blockade of the anterior scalene muscles have been shown to improve after ultimate surgical decompressions at the interscalene triangle. Anesthetic blockade of the scalene muscles, even with the addition of steroids, however, rarely produces any prolonged relief as patients are awaiting definitive surgery. The present study was undertaken to determine if more effective and prolonged relief might be obtained with electrophysiologically and fluoroscopically guided selective injection of the scalene muscles with botulinum toxin, which has been used in the past for treating conditions associated with spasm of cervical muscles. In 14 of 22 patients (64%) with a clinical diagnosis of TOS, there was more than a 50% reduction of symptoms measured by a 101-point scale for at least 1 month after botulinum chemodenervation of the scalene muscles. Only 4 of the 22 patients (18%) had a 50% reduction of symptoms for at least 1 month after injection with lidocaine and steroids. In no patient were the results of lidocaine and steroid injection superior to botulinum chemodenervation. Chemodenervation had a mean duration of effect of 88 days. No significant side effects were encountered with botulinum chemodenervation except for mild transient dysphagia in two cases. These results appear to demonstrate that botulinum chemodenervation of the scalene muscles may be helpful in alleviating symptoms in patients with TOS awaiting definitive surgical decompression.

Botulinum Toxins, Type A↗
PubMed1999

Endovascular, transperitoneal, and retroperitoneal abdominal aortic aneurysm repair: results and costs.

PURPOSE: Contemporary treatment of abdominal aortic aneurysms (AAA) includes transabdominal (TA), retroperitoneal (RP), and endovascular (EV) repair. This study compares the cost and early (30-day) results of a consecutive series of AAA repair by means of these three methods in a single institution. METHODS: A total of 125 consecutive AAA repairs between February 1993 and August 1997 were reviewed. Risk factors, 30-day morbidity and mortality rates, and hospital stay and cost were analyzed according to method of repair (TA, RP, EV). Cost was normalized by means of a conversion factor to maintain confidentiality. Cost analysis includes conversion to TA repair (intent to treat) in the EV group. RESULTS: One hundred twenty-five AAA repairs were performed with the TA (n = 40), RP (n = 24), or EV (n = 61) approach. Risk factors among the groups (age, coronary artery disease, hypertension, diabetes, chronic obstructive pulmonary disease, and cigarette smoking) were not statistically different, and thus the groups were comparable. The average estimated blood loss was significantly lower for EV (300 mL) than for RP (700 mL) and TA (786 mL; P>.05). Statistically significant higher cost for TA and RP for pharmacy and clinical laboratories (likely related to increased length of stay [LOS]) and significantly higher cost for EV in supplies and radiology (significantly reducing cost savings in LOS) were revealed by means of an itemized cost analysis. Operating room cost was similar for EV, TA, and RP. There were six perigraft leaks (9.6%) and six conversions to TA (9.6%) in the EV group. CONCLUSION: There were no statistically significant differences in mortality rates among TA, RP, and EV. Respiratory failure was significantly more common after TA repair, compared with RP or EV, whereas wound complications were more common after RP. Overall cost was significantly higher for TA repair, with no significant difference in cost between EV and RP. EV repair significantly shortened hospital stay and intensive care unit (ICU) use and had a lower morbidity rate. Cost savings in LOS were significantly reduced in the EV group by the increased cost of supplies and radiology, accounting for a similar cost between EV and RP. Considering the increased resource use preoperatively and during follow-up for EV patients, the difference in cost between TA and EV may be insignificant. EV repair is unlikely to save money for the health care system; its use is likely to be driven by patient and physician preference, in view of a significant decrease in the morbidity rate and length of hospital stay.

Aortic Aneurysm, Abdominal↗
PubMed1999

Endovascular interventions training and credentialing for vascular surgeons.

This article reviews issues concerning the training and credentialing of vascular surgeons in the use of endovascular techniques in the peripheral vascular system. These guidelines update a prior document that was published in 1993. They have been rewritten to accommodate the rapid evolution that has occurred in the field and to provide the appropriate requirements that a vascular surgeon should fulfill to be competent in the basic skills needed to safely and effectively perform all presently accepted diagnostic and therapeutic endovascular procedures.

Catheterization↗
PubMed1998

Thoracoscopic sympathectomy: techniques and outcomes.

Thoracic sympathectomy is an important option in the treatment of palmar hyperhidrosis and pain disorders. Earlier surgical procedures were highly invasive with known morbidity, acceptable outcome, and established recurrence rates that were the limitations to considering surgical treatment. Thoracoscopic sympathectomy is a minimally invasive procedure that allows detailed visualization of the sympathetic ganglia and minimal postoperative morbidity; however, outcome studies of this technique have been limited. The authors treated 39 patients with 60 thoracoscopic procedures, and the outcomes in this small series were equivalent to previously established open surgical techniques; however, operative moribidity rates, hospital stay, and time of return to normal activity were substantially reduced. Complications and recurrence of symptoms were also comparable to previous reports. Overall patient satisfaction and willingness to repeat the operative procedure ranged from 66 to 96% in all patients. Patients and physicians can consider minimally invasive thoracoscopic sympathectomy procedures as an option to treat sympathetically mediated disorders because of the procedure's reduced morbidity and at least equivalent outcome rates in comparison to other treatments.

Journal Article↗
PubMed1998

Lower extremity vascular reconstruction and endovascular surgery without preoperative angiography.

BACKGROUND: Recent studies have shown the feasibility of performing lower extremity revascularization based on noninvasive vascular studies alone. METHODS: We undertook a prospective study of patients with lower extremity ischemia who underwent revascularization without preoperative angiography. Preoperative evaluation was done with noninvasive studies including segmental pressures, ankle arm index, duplex scan, and selective use of magnetic resonance angiography. Intraoperative angiography and intra-arterial pressure measurements were used prior to revascularization. Standard patency analysis and follow-up examination were performed. RESULTS: In all, 47 patients underwent 65 procedures (27 iliac, 38 infrainguinal) over a 3-year period. Intraoperative angiography and operative findings correlated with the noninvasive studies. There was one immediate failure, and life table analysis demonstrated primary patency rates of 92% for iliac reconstruction (29 months) and 82% for infrainguinal reconstruction (40 months). CONCLUSION: Preoperative evaluation for lower extremity revascularization utilizing only noninvasive vascular testing gives satisfactory results and is a safe and potentially durable alternative to routine preoperative angiography in most cases.

Aged↗
PubMed1998

Thoracic outlet neurovascular compression: approaches to anatomic decompression and their limitations.

Surgical management of thoracic outlet syndrome (TOS) has evolved to include multiple approaches for anatomic decompression. The relevant anatomy and review of different operative approaches are presented. The supraclavicular and transaxillary approaches are the most commonly used, and each has relative advantages. A working knowledge of these approaches and their limitations will aid in successful management of TOS.

Axilla↗
PubMed1997

Laparoscopic aortobifemoral bypass.

PURPOSE: To determine the potential benefits of applying laparoscopic techniques for the intraabdominal insertion of aortofemoral grafts and to compare results with those of conventional surgery. METHODS: Having previously demonstrated the feasibility of a totally laparoscopic aortofemoral bypass technique using carbon dioxide peritoneal insufflation in a porcine model, we now report our first human experience with this laparoscopic technique in a 49-year-old man. RESULTS: The patient's postoperative course was marked by his minimal requirements for analgesia, early ambulation, and discharge from the hospital in the morning of the third postoperative day. CONCLUSIONS: The benefits of a laparoscopic approach to aortobifemoral bypass grafting in terms of financial savings and earlier rehabilitation in this patient was significant. This less-invasive procedure warrants further investigation.

Aorta, Abdominal↗