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Tam T Huynh

Publications and source records attributed to Tam T Huynh.

8 recordsLinked to original sources
PubMed2006

Catheter-direct thrombolysis versus pharmacomechanical thrombectomy for treatment of symptomatic lower extremity deep venous thrombosis.

BACKGROUND: Rheolytic mechanical thrombectomy using the AngioJet catheter (Possis Medical, Minneapolis, MN) has been shown to be effective in the treatment of deep venous thrombosis (DVT). Additional infusion of thrombolytic agents via the device creates a novel treatment strategy of pharmacomechanical thrombectomy (PMT), which further enhances thrombectomy efficacy. The purpose of the current study was to compare the treatment outcome in patients with symptomatic DVT who underwent either catheter-directed thrombolysis (CDT) or PMT intervention. METHODS: During a recent 8-year period, clinical records of all patients with symptomatic lower leg DVT undergoing catheter-directed interventions were evaluated. Patients were divided into 2 treatment groups: CDT or PMT. Comparisons were made with regards to the treatment outcome between the 2 groups. RESULTS: A total of 93 patients who underwent 98 catheter-directed interventions for DVT were included in the study. Among them, CDT or PMT was performed in 46 (47%) and 52 (53%) procedures, respectively. In the CDT group, complete or partial thrombus removal was accomplished in 32 (70%) and 14 (30%) cases, respectively. In the PMT cohort, complete or partial thrombus removal was accomplished in 39 (75%) and 13 (25%) cases, respectively. Venous balloon angioplasty and/or stenting in the CDT or PMT groups was necessary in 36 (78%) and 43 (82%), respectively (difference not significant [NS]). Patients in the CDT groups underwent a mean of 2.5 venograms during the hospital course, in contrast to 0.4 venograms per patient in PMT cohorts (P < .001). Immediate (<24 hours) improvement in clinical symptoms in CDT and PMT groups was achieved in 33 (72%) and 42 (81%) cases, respectively (NS). Significant reductions in the intensive care unit (ICU) and hospital lengths of stay was noted in the PMT group (0.6 and 4.6 days) when compared to the CDT group (2.4 and 8.4 days). During follow-up visits, the primary patency rates at 1 year of CDT and PMT groups were 64% and 68%, respectively (NS). Hospital cost analysis showed significant cost reduction in the PMT group compared to the CDT group (P < .01). CONCLUSIONS: PMT with adjunctive thrombolytic therapy is an effective treatment modality in patients with significant DVT. When compared to CDT, this treatment provides similar treatment success with reduced ICU, total hospital length of stay, and hospital costs.

Adult↗
PubMed2006

Characterization of the inflammatory and apoptotic cells in the aortas of patients with ascending thoracic aortic aneurysms and dissections.

OBJECTIVE: The histopathologic abnormality underlying ascending aortic aneurysm and dissection is medial degeneration, a lesion that is described as the noninflammatory loss of smooth muscle cells and elastic fibers. This study sought to determine whether inflammatory cells are present in medial degeneration and assess any possible contribution of these cells to apoptosis of smooth muscle cells. METHODS: Aortic specimens were obtained from patients undergoing prophylactic surgical repair of an ascending aortic aneurysm (n = 9) and type A dissection (n = 7), along with control patients dying of causes unrelated to aortic disease (n = 5). Immunohistochemical staining was performed to evaluate the presence of lymphocytes and macrophages, and markers of apoptosis were assessed in the aortas of patients with ascending aortic aneurysm and dissection. RESULTS: Immunohistochemical study indicated significantly more CD3+ cells in the aortas of patients with aneurysms or dissections than in control aortas (P = .020 and P = .0022, respectively). In addition, aortas of patients with aneurysms or dissections had more CD68+ cells (P = .01 and P = .005, respectively). CD3+ cells were localized in the media and surrounding the vasa vasorum in the adventitia. Cells yielding a positive result on in situ terminal transferase-mediated deoxyuridine triphosphate nick end-labeling were found in increased numbers in the aortas of patients with aneurysms or dissections relative to control aortas (P = .005 and P = .002, respectively). Furthermore, Fas and FasL were increased in the aortic samples from patients with aneurysms and dissections relative to control aortas. CONCLUSION: The coexistence of inflammatory cells with markers of apoptotic vascular cell death in the media of ascending aortas with aneurysms and type A dissections raises the possibility that activated T cells and macrophages may contribute to the elimination of smooth muscle cells and degradation of the matrix associated with thoracic aortic aneurysms and dissections.

Aortic Dissection↗
PubMed2006

Glomerular filtration rate is a predictor of mortality after endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Clinically evident renal disease is a risk factor for mortality after aneurysm repair. Serum creatinine is widely used as a measure of renal function in the preoperative evaluation of patients. Unfortunately, serum creatinine concentration is influenced by muscle mass, hydration status, and glomerular filtration rate (GFR). Calculated GFR, which takes predictors of muscle mass such as age, gender, and weight into account, is a more sensitive determinant of renal function than serum creatinine. We hypothesized that GFR would more accurately predict mortality after EVAR than serum creatinine. METHODS: We retrospectively evaluated our database of 398 patients who underwent EVAR with the AneuRx device between October 1999 and October 2004. There were 340 men and 58 women with a mean age of 73. GFR was calculated using the Cockcroft-Gault equation. The patients were divided into four quartiles by preoperative GFR: I (7 to 45), II (45 to 60), III (61 to 79), and IV (> or =80). Survival was estimated with the Kaplan-Meier method, and heterogeneity of mortality across strata was evaluated using the log-rank test. The GFR quartiles were compared with clinically accepted criteria for abnormal renal function (serum creatinine level > or =1.7). RESULTS: Actuarial survival at 48 months was 61.5%, 70.5%, 86.0%, and 85.7% for GFR quartiles I to IV, respectively (P < .003). Thirty-day mortality was 2.2% in quartile I, 3.2% in quartile II, and 0 in quartiles III and IV (P = .03 for q1 + q2 vs q3 + q4, P < .02 for q2 vs q3 + q4). Survival curves for quartiles II to IV were statistically indistinguishable, with quartile II running tangential to the two higher quartiles after the perioperative period. Quartile I fared significantly worse than the other three quartiles for the entire follow-up period (P < .005). According to American Kidney Foundation criteria (GFR <90), 83.3% of patients had abnormal renal function compared with 16.1% with abnormal serum creatinine (>1.7) (P < .0002). CONCLUSION: The risk of perioperative and long-term mortality in patients undergoing EVAR is more accurately stratified by using calculated GFR than serum creatinine alone. A GFR <45 is associated with decreased survival after EVAR. Perioperative mortality at a GFR of 45 to 60 is comparable with that of the lower quartile (GFR <45), but late survival is comparable with that of patients with GFR >60. The finding of increased risk of early mortality in patients in the 45 to 60 GFR range, with survivors enjoying good long-term outcome, suggests that these patients may most benefit from the use of alternative contrast agents and periprocedural renal protection techniques.

Aged↗
PubMed2005

Descending thoracic aortic aneurysm repair: 12-year experience using distal aortic perfusion and cerebrospinal fluid drainage.

BACKGROUND: The benefit of distal aortic perfusion and cerebrospinal fluid drainage over the "clamp and sew" technique during repairs of the descending thoracic aorta is still being debated. The purpose of this report is to analyze our experience with regard to neurologic deficit (paraplegia and paraparesis) and mortality using the adjuncts of distal aortic perfusion and cerebrospinal fluid drainage. METHODS: Between February 1991 and September 2004, we repaired 355 descending thoracic aortic aneurysms. Excluded from analysis were 29 patients who required profound hypothermic circulatory arrest as a result of transverse arch involvement and 26 patients with aortic rupture, leaving a group of 300 patients for which outcomes were analyzed. Mean patient age was 67 years, and 102 (34%) of the patients were women. The adjunct group of distal aortic perfusion and cerebrospinal fluid drainage used in 238 (79.3%) patients was compared with a group of 62 patients who underwent simple cross-clamp with or without the addition of a single adjunct. Multivariable data were analyzed by Cox regression. RESULTS: The incidence of neurologic deficit after all repairs was 2.3% (7 of 300 patients). The incidence of neurologic deficit (immediate and delayed) in the adjunct group was 1.3% (3 of 238 patients), and in the nonadjunct group was 6.5% (4 of 62 patients; p < 0.02). One case of delayed paraplegia occurred in each group. All neurologic deficits occurred in patients with aneurysmal involvement of the entire descending thoracic aorta (extent C; p < 0.02). Statistically significant predictors for neurologic deficit were the use of the adjunct (odds ratio [OR], 0.19; p = 0.02), previous repaired abdominal aortic aneurysm (OR, 7.0; p = 0.005), type C aneurysm (OR, 13.73; p = 0.02), and cerebrovascular disease history (OR, 4.7; p < 0.03). Thirty-day mortality was 8% (24 of 300 patients). Significant multivariate predictors of 30-day mortality were preoperative renal dysfunction (OR, 4.6; p < 0.01) and female sex (OR, 2.9; p < 0.03). CONCLUSIONS: Repairs of the descending thoracic aorta using the adjunct of distal aortic perfusion and cerebrospinal fluid drainage can be performed with a low incidence of neurologic deficit and an acceptable mortality. The use of the adjuncts should be considered during elective repairs of the descending thoracic aorta.

Adolescent↗
PubMed2005

Evolution of risk for neurologic deficit after descending and thoracoabdominal aortic repair.

BACKGROUND: Cross-clamp time has been reported to correlate with risk of neurologic deficit after thoracoabdominal aortic aneurysm repair. Introduction of cerebrospinal fluid drainage and distal aortic perfusion (adjunct) has greatly reduced the incidence of neurologic deficit. We reevaluated the effect of cross-clamp time before and after introduction of adjunct during a 13-year period. METHODS: Between 1991 and 2004, we repaired 1,106 thoracic and thoracoabdominal aortic aneurysms. Four hundred one patients were female and 705 were male (median age, 67 years). Selective use of adjunct was begun in late 1992, with its routine use by 1993. RESULTS: Aortic cross-clamp times have increased significantly (34 seconds/year; p < 0.0001) since 1991. Despite this increase in cross-clamp time, neurologic deficit rates have declined from the first to the fourth quartile (p < 0.02). This decrease in neurologic deficit is most pronounced with the extent II thoracoabdominal aortic aneurysms (21.1% to 3.3%). The use of the adjunct increased the cross-clamp time by a mean of 12 minutes (p < 0.0001), but was associated with a significant protective effect against neurologic deficit (odds ratio = 0.4; p < 0.0002). Although other previously established risk factors remained significantly associated with neurologic deficit, cross-clamp time is no longer significant. CONCLUSIONS: Adjunct significantly reduced the risk of neurologic deficit, despite increasing cross-clamp time. The use of the adjunct appears to blunt the effect of the cross-clamp time and may provide the surgeon the ability to operate without being hurried. Because cross-clamp time has been effectively eliminated as a risk factor with the use of the adjunct, using this variable to construct risk models becomes irrelevant in our experience.

Adolescent↗
PubMed2004

Determinants of early and late outcome for reoperations of the proximal aorta.

BACKGROUND: The purpose of this study was to investigate the cause of ascending aorta and aortic arch reoperations and to identify determinants of early and late outcome. METHODS: Between January 1991 and March 2003 we repaired aneurysms of the proximal aorta in 597 patients. Of these patients, 104 had reoperations for replacement of the ascending aorta, aortic root, or transverse aortic arch. Previous surgery was defined as any previous cardiac or proximal aortic repair. Median age was 60 years, and 29 of the patients (28%) were female. Indications for reoperation and replacement of the proximal aorta included acute type A dissection in 6 patients (5.8%), aneurysm with chronic dissection in 60 (57.7%), progression of aneurysm in 23 (22.1%), infection in 12 (1.5%), inflammatory disease in 2 (1.9%), and atheromatous disease in 1 (1.0%). Reoperations included aortic root replacement in 20 patients (19.2%), total arch replacement with elephant trunk in 28 (26.7%), ascending and proximal arch in 39 (37.5%), and ascending aorta in 27 (26.0%). The median interval between operations was 69 months. Retrograde cerebral perfusion was used in 80 (77%) cases. RESULTS: Chronic dissection was the most common indicator for reoperation in our population, followed by progression of aneurysm and infection. Thirty-day and in-hospital mortality was 13.5% (14 of 104) and 15.4% (16 of 104), respectively. Chronic obstructive pulmonary disease, renal dysfunction, and increased pump time were risk factors for mortality. Median follow-up was 5.02 years. Eight patients died during that period. Estimated survival at 1, 5, and 10 years was 83%, 80%, and 62%, respectively. Freedom from second proximal reoperations was 97.1% (10 of 104). Freedom from subsequent distal thoracic aortic repair was 84.6% (8 of 104). CONCLUSIONS: Reoperations of the ascending aorta and aortic arch can be performed safely with good long-term results. Patients with previous proximal aortic dissection repair need long-term surveillance. Renal dysfunction and chronic obstructive pulmonary disease must be carefully considered before reoperations of the proximal aorta.

Adolescent↗
PubMedDate not supplied

Chronically impaired endothelial vasoreactivity following oversized endovascular introducer sheath placement in porcine iliac arteries: implications for endovascular therapy.

The conventional endovascular aortic aneurysm procedure entails the placement of oversized introducer sheaths in relatively normal ileofemoral arteries to allow the delivery and deployment of endovascular prosthesis. Endoluminal manipulation with passage of oversized endoluminal devices can lead to endothelial denudation, resulting in impaired cellular function. The purpose of this study was to assess the time course of endothelial function with vasoreactivity following oversized endovascular sheath insertion ranging from 1 day to 16 weeks in normal porcine iliac arteries. Following oversized introducer sheath placement in bilateral iliac arteries, vasoreactivity was tested using both endothelium-dependent and -independent vasodilators. Intravascular ultrasonography showed a significant reduction in the luminal area at 12 and 16 weeks. This was similarly supported by morphometric analysis, which showed increased medial thickness with an elevated intima to media ratio at the same time course. Endothelium-dependent relaxation to bradykinin, calcium ionophore A23187, serotonin, and adenosine diphosphate all uniformly displayed attenuated endothelial dysfunction at all time points when compared with the control group. In contrast, endothelium-independent relaxation showed a decreased vasoresponsiveness at 4 weeks. In conclusion, this study underscored the detrimental and chronic endothelial dysfunction in a normal artery caused by oversized introducer sheath placement. Chronically impaired endothelial function may play a role leading to iliofemoral artery thrombosis or late occlusion, which were well-recognized adverse events following endovascular aneurysm procedures. Our study underscores the importance of appropriate patient selection to minimize potential sheath oversize and endograft device miniaturization to avoid vessel wall injury and maintain vasoreactivity.

Adenosine Diphosphate↗