Comparison of outcomes with surgical cut-down versus percutaneous transfemoral transcatheter aortic valve replacement: TAVR transfemoral access comparisons between surgical cut-down and percutaneous approach.

OBJECTIVES: The objective is to compare the short-term (30 days) and late (12 months) vascular adverse events in patients undergoing transfemoral (TF)-transcatheter aortic valve replacement (TAVR) by surgical cut-down (SC) vs. percutaneous (PC) approaches. BACKGROUND: Programs continue to utilize both approaches in TF-TAVR. There are limited data comparing outcomes by SC vs. PC approaches and long-term effects of endovascular intervention facilitated hemostasis on late vascular adverse events. METHODS: A total of 146 men and women aged 79.7 ± 10.0 years with severe aortic stenosis deemed extreme or high risk for surgery underwent TAVR via TF access. 61 had SC and 85 had PC approaches. Valve Academic Research Consortium (VARC-2) outcomes were assessed at an average of 12.1 months after TAVR. RESULTS: Hospital length of stay (LOS) post-TAVR was shorter for the PC group compared to the SC group (5.1 ± 3.9 vs. 8.2 ± 6.6 days; P < 0.001). More patients were discharged directly to home in the PC than the SC group (85.9% vs. 68.9%, P < 0.05). At 30 days, there were 13/61 (21.3%) and 16/85 (18.8%; P < 0.05) of any vascular events, and 2/61 (3.3%) and 2/85 (2.4%; P = 0.73) major vascular events in the SC and PC groups, respectively. There was no difference in all-cause mortality between the SC (14/61; 23%) and PC groups [17/85 (20%); P = 0.34]. There was no difference in any [4/33 (12%) vs. 3/43 (7%); P = 0.84] or major vascular adverse events [1/33 (3%) vs. 1/43 (2%); P = 0.79] in subjects that underwent adjunctive endovascular intervention compared to those who did not, respectively. There were no statistically significant univariate or multivariate predictors of any vascular event at 12 months when comparing SC to PC groups. CONCLUSION: For TF TAVR, the PC approach, when compared to the SC approach, is associated with a shorter hospital LOS and higher rate of direct discharge to home with similar risk of vascular complications, late vascular adverse events, and all-cause mortality at 12 months.

Prognostic utility of cardiovascular magnetic resonance upright maximal treadmill exercise testing.

BACKGROUND: Left ventricular wall motion abnormalities (LVWMA) observed during cardiovascular magnetic resonance (CMR) pharmacologic stress testing can be used to determine cardiac prognosis, but currently, information regarding the prognostic utility of upright maximal treadmill induced LVWMA is unknown. Our objective was to determine the prognostic utility of upright maximal treadmill exercise stress CMR. METHODS: One hundred and fifteen (115) men and women with known or suspected coronary arteriosclerosis and an appropriate indication for cardiovascular (CV) imaging to supplement ST segment stress testing underwent an upright treadmill exercise CMR stress test in which LVWMA were identified before and immediately after exercise. Personnel blinded to results determined the post-test incidence of cardiac events (cardiac death, myocardial infarctions [MI], and unstable angina warranting hospital admission or coronary arterial revascularization). RESULTS: All participants completed the testing protocol, with 90% completing image acquisition within 60 s of exercise cessation. MI or cardiac death occurred in 3% of individuals without and 17% of individuals with inducible LVWMA (p = 0.024). The combination of MI, cardiac death, and unstable angina warranting hospitalization occurred in 14% of individuals without and 47% of individuals with inducible LVWMA (p = 0.002). The addition of CMR imaging identified those at risk for future events (p = 0.002), as opposed to the electrocardiogram stress test alone (p = 0.63). CONCLUSIONS: In patients with or suspected of coronary arteriosclerosis and appropriate indication for imaging to supplement ST segment analysis during upright treadmill exercise, the presence of inducible LVWMA during treadmill exercise stress CMR supplements ST segment monitoring and helps identify those at risk of the future combined endpoints of myocardial infarction, cardiac death, and unstable angina warranting hospitalization.

Iatrogenic intrapericardial diaphragmatic hernia diagnosed by cardiovascular magnetic resonance.

Intrapericardial diaphragmatic hernias are very uncommon and are most typically caused by high-force blunt trauma. Other iatrogenic causes such as prior surgical formation of a pericardial window have been described, but are exceedingly rare. We present a case of an intrapericardial diaphragmatic hernia in a patient with a prior pericardial window in which the diagnosis was unclear using conventional imaging modalities, but was established using cardiovascular magnetic resonance.

Low to moderate dose anthracycline-based chemotherapy is associated with early noninvasive imaging evidence of subclinical cardiovascular disease.

OBJECTIVES: The goal of this study was to determine if low to moderate doses of anthracycline-based chemotherapy (Anth-bC) are associated with subclinical cardiovascular (CV) injury. BACKGROUND: Cancer survivors who receive Anth-bC experience premature CV events. It is unknown whether low to moderate doses of anthracyclines promote early subclinical CV disease manifested by deteriorations in left ventricular ejection fraction (LVEF) or increases in aortic stiffness, or if these doses are associated with changes in quality of life (QOL). METHODS: In 53 men and women with breast cancer, leukemia, or lymphoma, we assessed left ventricular volumes, LVEF, circumferential strain, aortic pulse wave velocity, late gadolinium enhancement, serum B-type natriuretic peptide, troponin I, and the impact of treatment on QOL before and 1, 3, and 6 months after receipt of Anth-bC. RESULTS: Participants averaged 50 ± 2 (range 19 to 80) years in age, 58% were women, 17% were black, and they each received a range of 50 to 375 mg/m(2) of doxorubicin-equivalent chemotherapy. Left ventricular end-systolic volume (48 ± 3 ml to 54 ± 3 ml; p = 0.02), left ventricular strain (-17.7 ± 0.4 to -15.1 ± 0.4; p = 0.0003), pulse wave velocity (6.7 ± 0.5 m/s to 10.1 ± 1 m/s; p = 0.0006), and QOL deterioration (15.4 ± 3.3 to 28.5 ± 3.9; p = 0.008) increased, whereas LVEF (58 ± 1% to 53 ± 1%; p = 0.0002) decreased within 6 months after low to moderate doses of Anth-bC. All findings persisted after accounting for age, gender, race (white/black), doxorubicin-equivalent dose, doxorubicin administration technique, comorbidities associated with CV events, and cancer diagnosis (p = 0.02 to 0.0001 for all). There were no new late gadolinium enhancement findings after 6 months. CONCLUSIONS: In these study patients, low to moderate doses of Anth-bC were associated with the early development of subclinical abnormalities of cardiac and vascular function that in other populations are associated with the future occurrence of CV events.

Incessant ventricular tachycardia and cardiogenic shock: a common presentation of an uncommon diagnosis.

Giant cell myocarditis is a rare and highly lethal disease that is characterized by a rapidly progressive course of biventricular dysfunction. The authors present a case of giant cell myocarditis that presented with incessant ventricular tachycardia and cardiogenic shock in which clinical improvement was achieved with immunosuppressive therapy.

Identification of structures within GABAA receptor alpha subunits that regulate the agonist action of pentobarbital.

Barbiturates act on GABA(A) receptors (GABARs) through three distinct mechanisms, resulting in positive allosteric modulation, direct activation, and inhibition. These effects are observed at different concentrations and are differentially affected by some mutations and by the receptor's subunit composition. Mammalian GABARs can be formed from a combination of 16 different subunit subtypes. Although the effect of barbiturates depends largely on the beta subunit, their agonist activity is substantially influenced by the alpha subunit subtype. Pentobarbital is a more effective agonist than GABA only when receptors contain an alpha6 subunit. Results from chimeric alpha1/alpha6 subunits suggested that structural differences within the extracellular N-terminal domain were responsible for this characteristic. Within this domain, we examined 15 amino acid residues unique to the alpha6 subtype. Each of these sites was individually mutated in the alpha6 subunit to the corresponding residue of the alpha1 subunit. The effect of the mutation on direct activation by pentobarbital was determined with whole-cell electrophysiological recordings. Our results indicate that only one of these mutations, alpha6(T69K), altered pentobarbital efficacy. This single mutation reduced the response to pentobarbital to a level intermediate to the wild-type alpha1beta1gamma2L and alpha6beta1gamma2L isoforms. The mutation did not affect the sensitivity of the receptor to GABA but did reduce the efficacy of etomidate, another i.v. anesthetic with activity similar to pentobarbital. The reverse mutation in the alpha1 subunit (K70T) did not alter the response to pentobarbital. This is the first identification of a structural difference in GABAR alpha subtypes that regulates direct activation by barbiturates.

Structural determinants of the pharmacological properties of the GABAA receptor alpha6 subunit.

GABA(A) receptors are responsible for fast inhibitory neurotransmission in the mammalian brain and are the targets for many clinical drugs that act as antiepileptics, anxiolytics, and sedatives. The pharmacological characteristics of the receptor are largely determined by its subunit composition. Compared with all other alpha subtypes, the alpha6 subtype confers unique pharmacological properties. In particular, alpha6-containing receptors are more sensitive to both the agonist GABA and the antagonist amiloride. Results from chimeric constructs of the alpha1 and alpha6 subunits suggested that structural differences within the extracellular N-terminal domain were responsible for both these characteristics. Within this domain, we examined 15 amino acid residues unique to the alpha6 subtype. Each of these sites was individually mutated in the alpha6 subunit to the corresponding residue of the alpha1 subunit. The mutated subunits were expressed in human embryonic kidney-293T cells along with wild-type beta3 and gamma2L subunits and sensitivity to GABA and amiloride determined with whole-cell electrophysiological recordings. Serine83 in the alpha6 subunit influenced sensitivity to both GABA and amiloride. Leucine174 and tyrosine175 were also found to contribute to inhibition by amiloride but did not affect GABA sensitivity. These structural differences are at least partly responsible for the unique pharmacological properties associated with the alpha6 subunit.

Fluoxetine increases GABA(A) receptor activity through a novel modulatory site.

Fluoxetine is a selective serotonin reuptake inhibitor used widely in the treatment of depression. In contrast to the proconvulsant effect of many antidepressants, fluoxetine has anticonvulsant activity. This property may be due in part to positive modulation of the GABA(A) receptors (GABARs), which mediate most fast inhibitory neurotransmission in the mammalian brain. We examined the effect of fluoxetine on the activity of recombinant GABARs transiently expressed in mammalian cells. Fluoxetine increased the response of the receptor to submaximal GABA concentrations but did not alter the maximum current amplitude. Sensitivity did not depend upon the beta- or gamma-subtype composition of the receptor when coexpressed with the alpha(1) subunit. Among the six alpha subtypes, only the alpha(5) subunit conferred reduced sensitivity to fluoxetine. The metabolite norfluoxetine was even more potent than fluoxetine. Mutations at residues in the alpha(5) subunit that alter its sensitivity to zinc or selective benzodiazepine derivatives did not affect potentiation by fluoxetine. This suggests that fluoxetine acts through a novel modulatory site on the GABAR. The direct positive modulation of GABARs by fluoxetine may be a factor in its anticonvulsant activity.