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Biomedical subjects

Robert S Dieter

Publications and source records attributed to Robert S Dieter.

At least 19 recordsLinked to original sources
PubMed2007

Invasive assessment of mitral regurgitation: comparison of hemodynamic parameters.

OBJECTIVES: We sought to analyze several new hemodynamic characteristics which address the interplay of left atrial (LA) and left ventricular (LV) pressures, as well as to re-analyze several other V wave characteristics employed in the determination of mitral regurgitation (MR) severity in order to determine which, if any, had adequate correlation with grade of MR for clinical utility. BACKGROUND: Invasive assessment of mitral regurgitation includes analysis of intracardiac pressures and LV angiography. The V wave, when obtained from the pulmonary capillary wedge position (PCWP), and its various characteristics are believed to be of limited value for prediction of MR severity. METHOD: We analyzed the transeptal pressure tracings of patients with various degrees of MR. Several relationships from the simultaneous pressure-time curves of the LA and LV were defined. Biplane left ventricular angiography was used to grade MR. Correlation between each parameter and MR grade was determined by calculating a Pearson correlation coefficient. RESULTS: The ratio of the area under the V wave to the LV systolic area (V(a)/LV(a)) best correlates with the degree of MR with a Pearson correlation coefficient of 0.60. The V(a)/LV(a) was significantly lower in patients with 0-1+ MR compared to > or =2+ MR (0.14 vs. 0.23 p = 0.002). CONCLUSIONS: Invasive hemodynamic assessment of MR severity could be enhanced by calculating our new ratio, V(a)/LV(a), due to its ability to account for LV work that is lost to the LA with a proportional decrease in forward or useful LV work with progressively increasing severity of MR.

Adult↗
PubMed2007

Cell transplantation for treatment of left-ventricular dysfunction due to ischemic heart failure: from bench to bedside.

Cell transplantation is an innovative technology that involves the implantation of a variety of myogenic and angiogenic cell types. The transplanted cells proliferate and augment left ventricular performance and therein ameliorate the heart failure symptoms. The concept of cell transplantation has followed the footsteps of angiogenesis starting as bench side research. The latter half of the decade saw the transformation of this potential mechanism to a promising therapy for ischemic heart failure. More than 150 patients have been treated with cellular transplantation worldwide. This novel application has the potential to revolutionize alternative therapeutic approaches to management of heart failure.

Animals↗
PubMed2006

Perforation complicating carotid artery stenting: the use of a covered stent.

Carotid artery angioplasty and stenting has emerged as an effective strategy for the treatment of significant carotid artery stenosis. Perforation during carotid artery stenting is a very rare potential complication of the procedure. We describe a case of carotid artery perforation that occurred during postdilation of the carotid artery stent. In our case this potentially serious complication was successfully treated with a covered stent-graft.

Aged↗
PubMed2006

Clinical experience with rotational atherectomy in patients with severe left ventricular dysfunction.

OBJECTIVE: To evaluate the safety and efficacy of rotational atherectomy (RA) in patients with severe left ventricular (LV) dysfunction. BACKGROUND: RA, using a rotating diamond-crystal burr, is most commonly used to open lesions with severe calcification or diffuse disease that may prove difficult to cross or dilate. However, RA generates microparticular debris that may attenuate the coronary microcirculation, inducing transient myocardial stunning and LV dysfunction. In fact, the manufacturer does not support RA use in patients with severe LV dysfunction. METHODS: We retrospectively identified patients with a LV ejection fraction < 30% who underwent RA in our institution over a 4-year period. The medical records were reviewed and risk factors for cardiac disease were recorded. The procedural reports and subsequent hospitalization records were reviewed to identify predetermined positive and negative outcomes. RESULTS: Twenty-three patients (17 males) who underwent RA with severe LV dysfunction (mean LVEF 21.3%) were identified. The majority of these patients had multivessel coronary artery disease, hypertension, hyperlipidemia and/or tobacco use. Also, a substantial subset had diabetes, renal insufficiency and or in-stent restenosis. RA was 100% successful in opening the lesions without any in-hospital procedure-related mortality. Three patients experienced periprocedural myocardial infarctions. One patient died from malignancy during hospitalization. There were no major adverse cardiac events at 30 days. CONCLUSION: The transient effect of RA on ventricular function did not adversely affect short-term outcomes in our study population. These results suggest that RA, when performed by experienced operators, is safe and feasible in patients with severe LV dysfunction.

Aged↗
PubMed2005

Carotid artery stenting: update.

"Extracranial carotid artery stenosis is responsible for approximately 20-30% of ischemic strokes. Traditionally, carotid artery stenosis has been treated with carotid endarterectomy. However, the low periprocedural complication rate and the mid term durability of carotid artery stenting has made it a competitive alternative treatment strategy. This update reviews the technical aspects of carotid artery stenting, clinical data supporting carotid artery stenting-particularly in high risk patients, and the complications associated with carotid artery stenting."

Blood Vessel Prosthesis Implantation↗
PubMed2005

Renovascular hypertension.

Renal artery disease is the most common cause of potentially curable secondary hypertension, with atherosclerosis as the major cause of renal artery stenosis. Fibromuscular dysplasia is a less common cause of renal artery stenosis and is most frequently observed in premenopausal women. Renal artery stenosis is likely to be underappreciated and is more common in patients with other vascular disease (e.g., coronary or peripheral arterial disease). The diagnosis of renal artery stenosis requires a high clinical index of suspicion as well as an appropriate imaging strategy, with currently effective diagnostic modalities including magnetic resonance imaging, computed tomography and renal artery duplex ultrasonography. The current treatment of choice for atherosclerotic renal artery stenosis is balloon angioplasty and secondary stenting, whereas angioplasty alone is the treatment for renal artery stenosis secondary to fibromuscular dysplasia. Expected outcomes following revascularization include improved blood pressure control and possibly renal preservation. Ongoing studies will hopefully identify patient characteristics that will achieve the most benefit from percutaneous revascularization as well as the impact of percutaneous revascularization with drug-eluting stents and embolic protection devices.

Humans↗
PubMed2004

Renal artery stenting using gadodiamide arteriography in patients with baseline renal insufficiency.

PURPOSE: To investigate whether a contrast agent containing gadodiamide can reduce the incidence of contrast-induced nephropathy associated with renal artery stenting in patients with preexisting renal insufficiency. METHODS: Between 1999 and 2002, gadodiamide-based arteriography was used in 20 patients (12 men; mean age 69 years) with significant baseline renal insufficiency (creatinine > or =1.7 mg/dL) undergoing renal artery stenting for > or =70% stenoses in 25 renal arteries. Baseline creatinine levels were compared to postprocedure and midterm follow-up levels. RESULTS: Procedural success was 100%. An average of 74 mL of gadodiamide contrast was used per case. Four patients received an additional 30 mL (mean) of iodinated contrast due to poor image quality with gadodiamide alone. There was no significant change in mean creatinine levels at discharge (2.9 mg/dL) compared to baseline (3.0 mg/dL, p=0.72). At midterm follow-up, mean creatinine levels (2.4 mg/dL) were significantly lower compared to baseline (p=0.004). CONCLUSIONS: Gadodiamide-based arteriography can be effectively used during RAS in patients with baseline renal insufficiency. This technique may enhance the renal-protective effect of renal artery stenting in this high-risk population with renal artery stenosis.

Aged↗
PubMed2003

Eversion endarterectomy complicating radial artery access for left heart catheterization.

The use of the radial artery for arterial access for left heart catheterization is gaining popularity. We report the first case of traumatic eversion endarterectomy following the removal of the arterial sheath after the cannulation of the radial artery. The patient has no long-term vascular compromise of the limb and did not require surgical intervention.

Aged↗
PubMed2003

Conservative vs. invasive treatment of aortocoronary saphenous vein graft aneurysms: Treatment algorithm based upon a large series.

BACKGROUND: The development of a saphenous vein graft aneurysm (SVGA) after coronary artery bypass graft surgery is a rare occurrence. There are approximately 60 cases reported in the literature, the majority being single case reports. There is no consensus on the treatment of SVGA. METHODS: Retrospective analysis of the patients treated with SVGA was performed at our institution. Demographic and co-morbidity data were acquired on the patients. Patients who underwent surgical treatment were compared to those treated conservatively with the primary outcome being survival time from diagnosis of the SVGA. RESULTS: Thirteen patients with 15 SVGA were identified. The average age at the time of the most recent coronary artery bypass grafting (CABG) was similar in the conservative and the surgically treated groups (55 vs. 56.5 years, respectively). The average number of grafts per patient at the most recent CABG was similar (3.83 vs. 4.0, respectively). The average time from CABG to diagnosis was similar in both the groups (12.6 vs. 15 years, respectively). The average survival from diagnosis was similar in both the groups (2.3 vs. 1.5 years, respectively, p>0.05). CONCLUSIONS: Early surgical treatment of SVGA does not provide longer short-term survival compared with conservative management. A treatment algorithm for SVGA based upon patient co-morbidities and aneurysm characteristics is proposed.

Adult↗