Faculty Bibliography

A 78 year-old man with remote type-A dissection presented with acute-onset dyspnea. Twenty-two years prior, treatment for his aortic disease required replacement of ascending and arch aneurysms with a Dacron graft using graft inclusion technique. He presented currently in cardiogenic shock. Echocardiography demonstrated new severe hypokinesis of all apical segments. Left-heart catheterization revealed a 120mmHg intra-graft gradient. CT arteriography was unrevealing, but intra-aortic ultrasound demonstrated critical intra-graft stenosis. A Palmaz stent was deployed in the stenotic region with gradient resolution. He later underwent aortic root replacement and ascending aneurysm repair (Bio-Bentall technique) and is doing well at 24 months.

BACKGROUND: The aim of this study was to determine the association between neutrophil-lymphocyte ratio (NLR) and severity of lower extremity peripheral artery disease (PAD). METHODS: A retrospective chart review identified 928 patients referred for peripheral angiography. NLR was assessed from routine pre-procedural hemograms with automated differentials and available in 733 patients. Outcomes of interest were extent of disease on peripheral angiography and target vessel revascularization. Median follow-up was 10.4months. Odds ratio (OR) [95% confidence intervals] was assessed using a logistic regression model. RESULTS: There was a significant association between elevated NLR and presence of severe multi-level PAD versus isolated suprapopliteal or isolated infrapopliteal disease (OR 1.11 [1.03-1.19], p=0.007). This association remained significant even after adjustment for age (OR 1.09 [1.01-1.17], p=0.02); age, sex, race, and body mass index (OR 1.08 [1.00-1.16], p=0.046); and age, sex, race, body mass index, hypertension, diabetes mellitus, coronary artery disease, and creatinine (OR 1.07 [1.00-1.15], p=0.049). After additional adjustment for clinical presentation, there was a trend towards association between NLR and severe multi-level PAD (OR 1.07 [1.00-1.15], p=0.056), likely limited by sample size. In patients who underwent endovascular intervention (n=523), there was no significant difference in rate of target vessel revascularization across tertiles of NLR (1st tertile 14.8%, 2nd tertile 14.1%, 3rd tertile 20.1%; p=0.32). CONCLUSION: In a contemporary cohort of patients undergoing peripheral angiography with possible endovascular intervention, elevated NLR was independently associated with severe multi-level PAD. Larger studies evaluating the association between this inexpensive biomarker and clinical outcomes are warranted.

Simulations were made of the pressure and velocity fields throughout an artery before and after removal of plaque using orbital atherectomy plus adjunctive balloon angioplasty or stenting. The calculations were carried out with an unsteady computational fluid dynamic solver that allows the fluid to naturally transition to turbulence. The results of the atherectomy procedure leads to an increased flow through the stenotic zone with a coincident decrease in pressure drop across the stenosis. The measured effect of atherectomy and adjunctive treatment showed decrease the systolic pressure drop by a factor of 2.3. Waveforms obtained from a measurements were input into a numerical simulation of blood flow through geometry obtained from medical imaging. From the numerical simulations, a detailed investigation of the sources of pressure loss was obtained. It is found that the major sources of pressure drop are related to the acceleration of blood through heavily occluded cross sections and the imperfect flow recovery downstream. This finding suggests that targeting only the most occluded parts of a stenosis would benefit the hemodynamics. The calculated change in systolic pressure drop through the lesion was a factor of 2.4, in excellent agreement with the measured improvement. The systolic and cardiac-cycle-average pressure results were compared with measurements made in a multi-patient study treated with orbital atherectomy and adjunctive treatment. The agreements between the measured and calculated systolic pressure drop before and after the treatment were within 3%. This excellent agreement adds further confidence to the results. This research demonstrates the use of orbital atherectomy to facilitate balloon expansion to restore blood flow and how pressure measurements can be utilized to optimize revascularization of occluded peripheral vessels.