Thach Nguyen

Left ventricular dysfunction causing ischemia in patients with patent coronary arteries

Background: New onset of heart failure (HF) is an indication for the assessment of coronary artery disease. The aim of this study was to clarify the mechanistic causes of new onset HF associated with ischemic electrocardiograph (EKG) changes and chest pain in patients with patent or minimally diseased coronary arteries. Methods: Twenty consecutive patients (Group A) were retrospectively reviewed if they had an history of new onset of HF, chest pain, electrocardiographic changes indicating ischemia (ST depression or T wave inversion in at least two consecutive leads and a negative coronary angiogram [CA]) and did not require percutaneous coronary intervention or coronary artery bypass grafting. A 1:1 matched cohort (Group B) was adopted to validate the results. Results: All patients had a negative CA. The majority of subjects in Group A had a higher left ventricular end diastolic pressure (LVEDP) when compared to the control group (p<0.05). Similarly, the aortic diastolic (AOD) pressure was lower in Group A than in Group B (p<0.05). In patients with elevated LVEDP and low AOD, with a coronary perfusion pressure (CPP) <20 mmHg, deep T wave inversion in two consecutive leads were more frequently observed. When the CPP was between 20-30 mmHg, a mild ST depression were more frequently recorded (p<0.05). Conversely, when the CPP was >30 mmHg, only mild non-specific ST-T changes or normal EKG were observed. Conclusions: In patients with HF and EKG changes suggestive of ischemia in at least two consecutive leads, a lower AOD could aggravate ischemia in patients with elevated left ventricular end diastolic pressure.

Evaluation of coronary flow conditions in complex coronary artery bifurcations stenting using computational fluid dynamics: Impact of final proximal optimization technique on different double-stent techniques☆

BACKGROUND/PURPOSEnComputational fluid dynamics (CFD) have been recently adopted in many fields of cardiovascular medicine and in interventional cardiology. Using CFD analysis we compared the use of different PCI procedures, with and without the utilization of a proximal optimization technique (POT), on a complex coronary artery bifurcation.nnnMETHODS/MATERIALSnFor the analysis, we considered a hypothetic model of a left anterior descending artery-diagonal Medina 1,1,1 bifurcation type with a diameter of the proximal main branch (MB) and the side branch (SB) set at 3.5mm and 2.5mm, respectively. The bifurcation angle has been set to 50°. For the stent simulation, we reconstructed a third-generation, ultra-thin strut everolimus-eluting stent (ORSIRO stent, Biotronik IC, Bulack, Switzerland).nnnRESULTSnThe Nano-crush and the modified T techniques seem able to restore the most physiologic fluid dynamic profile. Conversely, the DK-crush and the culotte demonstrated an intermediate and worst effect, respectively. The addition of a final POT resulted favorably for both Nano-crush and reverse modified T techniques, whereas a neutral and lack of significant effects have been observed for the DK-crush and culotte technique, respectively.nnnCONCLUSIONnDifferent double-stenting techniques (DST) have a different impact on coronary flow physiology. Both Nano-crush and modified T techniques achieved the most physiologic profile. The addition of a final POT appears to be a favourable step for both Nano-crush and modified T.

Complex coronary bifurcation treatment by a novel stenting technique: Bench test, fluid dynamic study and clinical outcomes

We assess the mid‐term outcomes of ultrathin biodegradable polymer double stenting using a very minimal crushing (Nano‐Crush) technique in large complex coronary bifurcation.

Medical Therapy for Critical Limb Ischemia

Critical limb ischemia (CLI) is defined as the combination of evidence of ischemia together with any of ischemic rest pain, nonhealing ulcers, or gangrene. CLI causes disabling symptoms, leading to high amputation and mortality rate within the first year or at 5 years. The aims of management in patients with CLI are to relieve ischemic pain, heal ulcers, prevent limb loss, reduce mortality, and improve function and quality of life. Current recommendations state that all patients with CLI must receive antiplatelet therapy, stop smoking, and be screened and treated for hyperlipidemia, hypertension, and diabetes mellitus in addition to modification of lifestyle. Other possible options include antithrombotic agents, anticoagulants, vasodilators, pain medication, spinal cord stimulation, hyperbaric therapy, gene therapy, and cell therapy. Their clinical efficacy or ineffectiveness will be discussed.

Evaluation of potential substrates for restenosis and thrombosis in overlapped versus edge-to-edge juxtaposed bioabsorbable scaffolds: Insights from a computed fluid dynamic study

BACKGROUND/PURPOSEnMultiple BRSs and specifically the Absorb scaffold (BVS) (Abbott Vascular, Santa Clara, CA USA) have been often used to treat long diffuse coronary artery lesions. We evaluate by a computational fluid dynamic(CFD) study the impact on the intravascular fluid rheology on multiple bioabsorbable scaffolds (BRS) by standard overlapping versus edge-to-edge technique.nnnMETHODS/MATERIALSnWe simulated the treatment of a real long significant coronary lesion (>70% luminal narrowing) involving the left anterior descending artery (LAD) treated with a standard or edge-to-edge technique, respectively. Simulations were performed after BVS implantations in two different conditions: 1) Edge-to-edge technique, where the scaffolds are kissed but not overlapped resulting in a luminal encroachment of 0.015cm (150μm); 2) Standard overlapping, where the scaffolds are overlapped resulting in a luminal encroachment of 0.030cm (300μm). After positioning the BVS across the long lesion, the implantation procedure was performed in-silico following all the usual procedural steps.nnnRESULTSnAnalysis of the wall shear stress (WSS) suggested that at the vessel wall level the WSS were lower in the overlapping zones overlapping compared to the edge-to-edge zone (∆=0.061Pa, p=0.01). At the struts level the difference between the two WSS was more striking (∆=1.065e-004 p=0.01) favouring the edge-to-edge zone.nnnCONCLUSIONSnOur study suggested that at both vessel wall and scaffold struts levels, there was lowering WSS when multiple BVS were implanted with the standard overlapping technique compared to the edge-to-edge technique. This lower WSS might represent a substrate for restenosis, early and late BVS thrombosis, potentially explaining at least in part the recent evidences of devices poor performance.

GW27-e1219 New Test to Diagnose Vasovagal Syncope

Current diagnosis of vasovagal syncope is by exclusion after all the other tests are negative. Other tests include CT scan of the head, carotid arterial Doppler and tilt table test which are time consuming, non-specific, costly and not cost effective.nnPatients with history of vasovagal syncope who