Network


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

Hotspot


Dive into the research topics where Yannan Shen is active.

Publication


Featured researches published by Yannan Shen.


The Annals of Thoracic Surgery | 1999

601 octogenarians undergoing cardiac surgery: outcome and comparison with younger age groups

Joseph M. Craver; John D. Puskas; William W Weintraub; Yannan Shen; Robert A. Guyton; John Parker Gott; Ellis L. Jones

BACKGROUND Cardiac valve replacement and coronary artery bypass graft surgery (CABG) are being applied with increasing frequency in patients 80 years of age and older. METHODS Six hundred one consecutive patients older than 80 years, undergoing cardiac surgery between 1976 and 1994 (CABG with saphenous vein graft, 329 [54.7%]; CABG with left internal mammary artery, 101 [16.8%]; CABG + valve, 80 [13.3%]; isolated aortic valve replacement, 71 [11.8%]; isolated mitral valve replacement, 18 [3.0%]), were studied retrospectively to assess short- and long-term survival. They were compared with 11,386 patients aged 60 to 69 years and 5,698 patients aged 70 to 79 years undergoing similar procedures during the same time interval. RESULTS In comparison with patients 60 to 69 years old, more octogenarians were women (44.4% versus 25.6%, p<0.0001), had class IV angina (54.1% versus 38.9%, p<0.0001), and had congestive heart failure class IV (4.9% versus 3.0%, p = 0.0001). In-hospital death rates (9.1% versus 3.4%, p<0.0001) and stroke (5.7% versus 2.6%, p<0.0001) reflected these adverse clinical risk factors. However, Q-wave infarction tended to be less frequent (1.5% versus 2.6%, p = 0.102). Interestingly, hospital mortality (9.1% versus 6.7%, p = 0.028) was only slightly increased, and stroke (5.7% versus 4.7%, p = 0.286) was not more common in octogenarians than in patients 70 to 79 years old. Late-survival curves have similar slopes for the first 5 years in all clinical subgroups. However, after 5 years there is a more rapid decline in octogenarians than in younger age groups. Median 5-year survival was 55% for patients older than 80 years, 69% for patients 70 to 79 years, and 81% for patients 60 to 69 years old. CONCLUSIONS When appropriately applied in selected octogenarians, cardiac surgery can be performed with acceptable mortality and excellent 5-year survival.


American Journal of Cardiology | 1995

Predictors of groin complications after balloon and new-device coronary intervention

Ron Waksman; Spencer B. King; John S. Douglas; Yannan Shen; Heather Ewing; Lorena Mueller; Ziyad Ghazzal; William S. Weintraub

We reviewed the clinical course of 5,042 patients who underwent percutaneous transluminal coronary angioplasty (PTCA) using balloons or new devices: (stent, laser, directional and rotational atherectomy). A vascular complication was defined as the formation of a groin hematoma, bleeding, pseudoaneurysm, fistula, or the need for surgical repair. Vascular complications occurred in 309 (6.1%) patients, and 117 (2.3%) required vascular repair; among these patients, surgery was performed for correction of an an arteriovenous fistula in 12%, repair of pseudoaneurysm in 72%, repair for expanding hematoma and femoral artery lacerations in 10%, and retroperitoneal bleeding in 6%. The correlates of vascular complications were older age (66.8 vs 62.1 years; p < 0.0001), female gender (43% vs 26%; p < 0.0001), increased weight (82.1 +/- 16.46 vs 78.0 +/- 16.6 kg; p < 0.001), higher systolic blood pressure (140 +/- 25 vs 134 +/- 20 mm Hg; p < 0.001), increased heparin dose during the procedure (14,352 +/- 3,879 vs 13,599 +/- 3,508 IU; p = 0.001), administration of heparin after the procedure (232 vs 2,985 patients; p < 0.0001) and intracoronary stenting (14.9% vs 3.5%; p < 0.0001). Fifteen patients of 214 (7.0%) who underwent stent implantation had surgical repair. Vascular complications were not related to the size of the arterial sheath (8.11 +/- 0.8 vs 8.8 +/- 0.7Fr; p = 0.11) and the use of devices other than stents (laser, atherectomy) did not increase the rate of vascular complications.


The Annals of Thoracic Surgery | 1999

Treatment of moderate mitral regurgitation and coronary disease by coronary bypass alone: late results ☆

Ignacio G. Duarte; Yannan Shen; Malcolm J. MacDonald; Ellis L. Jones; Joseph M. Craver; Robert A. Guyton

BACKGROUND In cases of moderate mitral regurgitation and coronary artery disease operative strategy continues to be debated between coronary artery bypass grafting alone and concomitant valve replacement or repair. We previously reported on 58 patients with moderate mitral regurgitation who had coronary artery bypass grafting between 1977 and 1983. We present the late results for this original cohort (test group), and a matched control group of coronary artery bypass grafting patients without mitral regurgitation (n = 58). METHODS AND RESULTS In the original cohort, the hospital mortality rate was 3.4% (2 of 58), and 80.4% (45 of 56) of hospital survivors were alive at the time of initial follow-up (mean, 4.3+/-2.3 years). Hospital mortality in the control group was 6.9% (4 of 58 patients). Follow-up was 98.2% (108 of 110 patients) complete, with a mean follow-up time of 10.3+/-5.5 years. Kaplan-Meier curves for hospital survivors showed similar 5- and 10-year survival rates between the two groups (p = 0.59). On multivariate analysis, age 65 years or more, congestive heart failure class III or IV, and pulmonary capillary wedge pressure more than 17 mm Hg were significant (p < 0.05) independent predictors of diminished survival in the test group. CONCLUSIONS Patients with moderate mitral regurgitation and coronary artery disease treated solely with coronary artery bypass grafting had acceptable early and late results. Moderate mitral regurgitation at the time of revascularization does not always warrant operative correction.


The Annals of Thoracic Surgery | 1994

Interaction of age and coronary disease after valve replacement: Implications for valve selection

Ellis L. Jones; William S. Weintraub; Joseph M. Craver; Robert A. Guyton; Yannan Shen

The interaction of patient age and the presence of coronary artery disease (CAD) and its influence on survival were examined in 3,644 patients undergoing either aortic (AVR) or mitral (MVR) valve replacement with or without coronary artery bypass grafting (CABG) between 1974 and 1991. Emergency procedures were performed much more frequently in those undergoing MVR and CABG than in those undergoing AVR and CABG (18.8% and 6.7%, respectively). The adverse effect of CAD on median survival for patients of all ages undergoing either AVR or MVR was statistically significant (AVR without CAD 11.8 versus 8.7 years with CAD; MVR without CAD 12.7 versus 7.3 years with CAD; p < 0.0001). Survival in patients younger than 70 years without CABG who underwent either AVR or MVR was quite good (< 60 years: AVR, > 14 years; MVR, 15.4 years; 60 to 69 years: AVR, 10.4 years; MVR, 11.4 years). The most profound effect of CAD on patient survival after valve replacement was observed in patients 60 to 69 years of age who underwent MVR, in whom the median survival without CABG was 11.4 years versus 5.5 years with CABG (p < 0.0001). An emergency operative status was associated with a reduced early and late survival for those patients undergoing MVR, particularly those with CAD. By relating the Cox proportional hazard models for valve survival to patient survival, we found that, in those patients 70 years and older with and without CAD who underwent either AVR or MVR, the median patient survival was reduced sufficiently (5.5 versus 8.1 years) to justify use of a bioprosthetic valve.(ABSTRACT TRUNCATED AT 250 WORDS)


American Heart Journal | 1997

Short- and long-term outcome of narrowed saphenous vein bypass graft: A comparison of Palmaz-Schatz stent, directional coronary atherectomy, and balloon angioplasty

Ron Waksman; William S. Weintraub; Ziyad Ghazzal; Neal A. Scott; Yannan Shen; Spencer B. King; John S. Douglas

Percutaneous treatment of saphenous vein graft (SVG) stenosis has been established as an alternative to repeat coronary artery bypass grafting. Intracoronary Palmaz-Schatz stent (PSS) and directional coronary atherectomy (DCA) have been suggested to provide better short- and long-term results than balloon angioplasty. Records of 840 patients with 931 SVG lesions treated with PSS (121 patients, 132 lesions), DCA (103 patients, 107 lesions), and balloon angioplasty (616 patients, 692 lesions) were reviewed. Inhospital and long-term outcome were compared among treated groups. The groups had similar clinical and angiographic baseline characteristics except for higher previously dilated grafts in the stent group and graft location among devices. Stent placement was angiographically successful in 99%, DCA in 95%, and balloon angioplasty in 93% of the lesions (p = 0.03). Quantitative angiography revealed a larger lumen diameter after procedure after PSS (3.2 mm) and DCA (3.1 mm) compared with 2.4 mm after balloon angioplasty (p = 0.0001). Angiographic complications (abrupt closure, severe dissections, or distal embolization) were evident in eight (6.1%) lesions after PSS placement, in 17 (15.9%) after DCA, and in 61 (8.8%) after balloon angioplasty. Serious in-hospital clinical complications (death, emergency coronary artery bypass grafting, or Q-wave myocardial infarction) were similar among devices. Survival rates were similar among the groups (p = 0.15). Repeat revascularization at follow-up was reported in 58 (60.4%) of patients after PSS, in 48 (51.1%) after DCA, and in 280 (49.4%) after balloon angioplasty. Correlates of additional revascularization at follow-up were older grafts, calcific lesions, previously dilated grafts, longer lesions, and patients with lower ejection fractions (odds ratio 1.06, 1.34, 1.43, 1.04, and 1.01, respectively). Correlates of mortality rate at follow-up were older patients, patients with lower ejection fractions, and distal embolization (odds ratio 1.04, 1.04, and 1.92, respectively). These data suggest that in patents with SVG stenosis the initial success and morbidity rates are similar when comparing PSS and DCA with balloon angioplasty. Although a larger lumen is obtained with PSS and DCA, patients who underwent balloon angioplasty had similar rates of cardiac events and requirements for additional procedures at follow-up.


The Annals of Thoracic Surgery | 1995

Should the freehand allograft be abandoned as a reliable alternative for aortic valve replacement

Ellis L. Jones; Vipul B. Shah; Jack S. Shanewise; Tomas D. Martin; Randolph P. Martin; Jorge A. Coto; Ruth Broniec; Yannan Shen

Cryopreserved aortic allografts were used for aortic valve replacement in 80 patients between 1986 and 1994 (infracoronary in 46 and complete root replacement in 34). Hospital mortality was 6.3% (5/80) with all deaths occurring in the infracoronary group. Three of five deaths were in patients with endocarditis and valve ring abscess. Left ventricular-aortic mean pressure gradients across the allograft valves were significantly lower for root replacement patients (mean, 9.0 +/- 6.9 mm Hg versus 18.1 +/- 8.7 mm Hg for infracoronary patients) (p = 0.0001). No patient having root allograft replacement had early echocardiographic aortic insufficiency greater than grade 1 versus 28% of those having infracoronary implantations. Late aortic insufficiency of grade 2 or greater was seen in 46% of patients having infracoronary implantation versus 17% of patients having root implantation. Nine patients had explantation of an aortic allograft (eight infracoronary and one root). Reasons for explantation were as follows: endocarditis (three infracoronary, one root), technical (three infracoronary), undiagnosed idiopathic hypertrophic subaortic stenosis (1 patient), and prolapsing infracoronary leaflet (1 patient). Actuarial freedom from grade 3 and 4 aortic insufficiency or explantation was 77% at 7 years for infracoronary implantations. We conclude that the infracoronary aortic allograft has an unacceptable frequency of late insufficiency and its use in this position should be abandoned. The substantial incidence of late endocarditis in the infracoronary (free-hand) aortic allograft was surprising.(ABSTRACT TRUNCATED AT 250 WORDS)


The Annals of Thoracic Surgery | 1995

Coronary artery bypass grafting in patients after failure of intracoronary stenting

Joseph M. Craver; Alexander G. Justicz; William S. Weintraub; Yannan Shen; Robert A. Guyton; John Parker Gott; Ellis L. Jones

BACKGROUND Intracoronary stents are being used to treat acute and threatened closure after percutaneous transluminal coronary angioplasty and to prevent restenosis. METHODS The outcomes of 68 patients having coronary artery bypass grafting after stent placement were reviewed. The mean age was 60.5 +/- 9.7 years, and 71% were male. Thirty-seven percent had hypertension, 13% had diabetes, 62% had class III or IV angina, 60% had multivessel disease, and 40% had sustained a prior myocardial infarction. Fifty-three patients underwent emergency operation, 22 with hemodynamic collapse immediately after percutaneous transluminal coronary angioplasty, and 7 others required urgent revascularization within 24 hours of angioplasty. Seventeen underwent coronary artery bypass grafting for acute closure of the stented vessel several days after the angioplasty procedure. RESULTS There was no correlation between urgency of the procedure, previous infarction, or previous coronary artery bypass grafting with successful procedure. The in-hospital mortality was 4.4%, 21% had a Q-wave myocardial infarction, and 1.5% sustained a stroke. Ejection fraction was the only correlate of long-term mortality. CONCLUSIONS Coronary artery injury for which stents are placed for acute or threatened occlusion or to prevent restenosis but then fail, thus necessitating coronary artery bypass grafting, can be treated successfully. Although the rate of Q-wave myocardial infarction is substantial and related to the initial ischemic insult, the long-term survival and event rates are excellent with prompt surgical revascularization.


American Journal of Cardiology | 1996

“Bailout” coronary stenting in patients with a recent myocardial infarction

Clifford N. Thomas; William S. Weintraub; Yannan Shen; Ziyad Ghazzal; John S. Douglas; Spencer B. King; Neal A. Scott

Patients who underwent bailout intracoronary stenting within 7 days of a myocardial infarction had lower clinical and angiographic success rates and a higher incidence of emergent coronary artery bypass graft surgery than patients who underwent bailout stenting without a history of a recent myocardial infarction. In addition, there was a trend toward more cardiac events after discharge in patients who received stents after a recent myocardial infarction.


Catheterization and Cardiovascular Diagnosis | 1997

Intracoronary stent implantation using a single high-pressure perfusion balloon catheter

Ron Waksman; Colin D. Shafer; Ki Bae Seung; Yannan Shen; William S. Weintraub; Spencer B. King

Currently, the recommended strategy for Palmaz-Schatz intracoronary stent implantation is to use two balloons: an undersized balloon for predilation to facilitate a channel for the stent and a high pressure balloon for postdilation to obtain good apposition of the struts into the vessel wall. We reported our experience using the perfusion balloon as the initial balloon to dilate intracoronary lesions and demonstrated a reduction in the total number of balloons used per angioplasty procedure. The objective of this study was to examine whether a single balloon could effectively be used for stent implantation. The study population included 95 patients who underwent elective intracoronary stent placement to 100 lesions using 110 Palmaz-Schatz stents by nine individual operators. Lesions were predilated with an ACS RX LIFESTREAM balloon at a low pressure of 4-6 atm (mean 5.7 +/- 2.6). After stent deployment, the same balloon was used at a high pressure (mean 16.2 +/- 1.2). Mean balloon size, which was chosen as the stent size, was 3.4 +/- 0.4 mm. Comparison of this strategy with the recommended strategy of 68 consecutive elective stent deployments at a single center during the same time was performed. Stent implantation using a single balloon strategy was angiographically successful in 99 of 100 (99.0%) lesions. The single balloon strategy was associated with a balloon burst rate of 9.1%. The number of balloons used per stent deployment was 1.2 vs. 2.4 using the recommended strategy (P < 0.0001). There was no evidence of stent thrombosis, any MI, or target lesion revascularization during the procedure and hospitalization. One in-hospital death as a result of nonhemorrhagic stroke was documented in the treated group. We concluded that using a single high pressure perfusion balloon for pre and postdilation in patients undergoing elective stent placement is safe and reduces the number of balloons used per procedure.


Journal of the American College of Cardiology | 1998

Clinical Outcome of Diabetic Patients After Palmaz-Schatz Stent Implantation

R. Blankenbaker; Ziyad M.B. Ghazzal; William S. Weintraub; Yannan Shen; Spencer B. King

Collaboration


Dive into the Yannan Shen's collaboration.

Top Co-Authors

Avatar

William S. Weintraub

Christiana Care Health System

View shared research outputs
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