Prevalence and progression of LV dysfunction and dyssynchrony in patients with new-onset LBBB post TAVR

BACKGROUND

The impact of new-onset left bundle branch block (N-LBBB) developing after Transcatheter Aortic Valve Replacement (TAVR) on cardiac function and mechanical dyssynchrony is not well defined.

METHODS

We retrospectively screened all patients who underwent TAVR in our centre between Oct 2018 and Sept 2021 (n = 409). We identified 38 patients with N-LBBB post-operatively (of which 28 were persistent and 10 were transient), and 17 patients with chronic pre-existent LBBB (C-LBBB). We excluded patients requiring pacing post TAVR. For all groups, we retrospectively analysed stored echocardiograms at 3 time points: before TAVR (T0), early after TAVR (T1, 1.2 ± 1.1 days), and late follow-up (T2, 1.5 ± 0.8 years), comparing LV mass and volumes, indices of LV function (LV ejection fraction, LVEF; global longitudinal strain, GLS), and mechanical dyssynchrony indices (systolic stretch index, severity of septal flash).

RESULTS

At baseline (T0), C-LBBB had worse cardiac function, and larger LV volumes and LV mass, compared with patients with N-LBBB. At T1, N-LBBB resulted in mild dyssynchrony and decreased LVEF and GLS. Dyssynchrony progressed at T2 in persistent N-LBBB but not C-LBBB. In both groups however, LVEF remained stable at T2, although individual response was variable. Patients with better LVEF at baseline demonstrated a higher proportion of developing LBBB-induced LV dysfunction at T2. Lack of improvement of LVEF immediately after TAVR predicted deteriorating LVEF at T2. In transient LBBB, cardiac function and most dyssynchrony indices returned to baseline.

CONCLUSIONS

N-LBBB after TAVR results in an immediate reduction of cardiac function, in spite of only mild dyssynchrony. When LBBB persists, patients with better cardiac function before TAVR are more likely to have LBBB-induced LV dysfunction after TAVR.

The Impact of Patient Characteristics and Antiplatelet Regimes on Clot Microstructure in Patients Treated for ST Elevation Myocardial Infarction: Clot Microstructure can Evaluate Therapeutic Efficacy

BACKGROUND

Unfavourable clot microstructure is associated with adverse outcomes in ST elevation myocardial infarction (STEMI). We investigated the effect of comorbidities and anti-platelet treatment on clot microstructure in STEMI patients using fractal dimension (d_f), a novel biomarker of clot microstructure derived from the visco-elastic properties of whole blood.

METHODS

Patients with STEMI (n = 187) were recruited sequentially receiving aspirin with Clopidogrel (n = 157) then Ticagrelor (n = 30). Patient characteristics and blood for rheological analysis obtained. We quantified d_f using sequential frequency sweep tests to obtain the phase angle of the Gel Point which is synonymous with the clot microstructure.

RESULTS

Higher d_f was observed in males (1.755 ± 0.068) versus females (1.719 ± 0.061, p = .001), in patients with diabetes (1.786 ± 0.067 vs 1.743 ± 0.046, p < .001), hypertension (1.760 ± 0.065 vs 1.738 ± 0.069, p = .03) and previous MI (1.787 ± 0.073 vs 1.744 ± 0.066, p = .011) compared to without. Patients receiving Ticagrelor had lower d_f than those receiving Clopidogrel (1.708 ± 0.060 vs 1.755 ± 0.067, p < .001). Significant correlation with d_f was found with haematocrit (r = 0.331, p < .0001), low-density lipoprotein (LDL) (r = 0.155, p = .046) and fibrinogen (r = 0.182, p = .014). Following multiple regression analysis, diabetes, LDL, fibrinogen and haematocrit remained associated with higher d_f while treatment with Ticagrelor remained associated with lower d_f.

CONCLUSIONS

The biomarker d_f uniquely evaluates the effect of interactions between treatment and underlying disease on clot microstructure. STEMI patients with diabetes and elevated LDL had higher d_f, indicating denser clot. Ticagrelor resulted in a lower d_f than Clopidogrel signifying a less compact clot.

3D Optical Coherence Tomography Reveals Fractured Coronary Stent as Cause of Acute Myocardial Infarction

A 61-year-old patient who underwent emergent coronary angiography and drug-eluting stent implantation of a calcified left anterior descending coronary artery returned 2 days later with recurrence of chest pain and anterior ST-segment elevation. Three-dimensional OCT revealed extensive fracture and distortion of the struts in the distal portion of a stent, presumably caused by aggressive postdilation at the time of implantation. This was managed successfully with the insertion of a new coronary stent inside the damaged stent segment.

Randomized trial of preventive angioplasty in myocardial infarction

BACKGROUND

In acute ST-segment elevation myocardial infarction (STEMI), the use of percutaneous coronary intervention (PCI) to treat the artery responsible for the infarct (infarct, or culprit, artery) improves prognosis. The value of PCI in noninfarct coronary arteries with major stenoses (preventive PCI) is unknown.

METHODS

From 2008 through 2013, at five centers in the United Kingdom, we enrolled 465 patients with acute STEMI (including 3 patients with left bundle-branch block) who were undergoing infarct-artery PCI and randomly assigned them to either preventive PCI (234 patients) or no preventive PCI (231 patients). Subsequent PCI for angina was recommended only for refractory angina with objective evidence of ischemia. The primary outcome was a composite of death from cardiac causes, nonfatal myocardial infarction, or refractory angina. An intention-to-treat analysis was used.

RESULTS

By January 2013, the results were considered conclusive by the data and safety monitoring committee, which recommended that the trial be stopped early. During a mean follow-up of 23 months, the primary outcome occurred in 21 patients assigned to preventive PCI and in 53 patients assigned to no preventive PCI (infarct-artery-only PCI), which translated into rates of 9 events per 100 patients and 23 per 100, respectively (hazard ratio in the preventive-PCI group, 0.35; 95% confidence interval [CI], 0.21 to 0.58; P<0.001). Hazard ratios for the three components of the primary outcome were 0.34 (95% CI, 0.11 to 1.08) for death from cardiac causes, 0.32 (95% CI, 0.13 to 0.75) for nonfatal myocardial infarction, and 0.35 (95% CI, 0.18 to 0.69) for refractory angina.

CONCLUSIONS

In patients with STEMI and multivessel coronary artery disease undergoing infarct-artery PCI, preventive PCI in noninfarct coronary arteries with major stenoses significantly reduced the risk of adverse cardiovascular events, as compared with PCI limited to the infarct artery. (Funded by Barts and the London Charity; PRAMI Current Controlled Trials number, ISRCTN73028481.).

Association of the arterial access site at angioplasty with transfusion and mortality: the M.O.R.T.A.L study (Mortality benefit Of Reduced Transfusion after percutaneous coronary intervention via the Arm or Leg)

BACKGROUND

Bleeding and transfusion after percutaneous coronary intervention (PCI) are known predictors of mortality. Transradial arterial access reduces bleeding and transfusion related to femoral access complications, although its association with mortality is unknown.

OBJECTIVE

To determine the association of arterial access site (radial or femoral) with transfusion and mortality in unselected PCIs.

DESIGN, SETTING AND PATIENTS

By data linkage of three prospectively collated provincial registries, 38,872 procedures in 32,822 patients in British Columbia were analysed. The association between access site, transfusion and outcomes was assessed by logistic regression, propensity score matching and probit regression.

MAIN OUTCOME MEASURES

30-Day and 1-year mortality.

RESULTS

1134 (3.5%) patients had at least one blood transfusion. Transfused patients had a significantly increased 30-day and 1-year mortality, adjusted odds ratio (95% CI) 4.01 (3.08 to 5.22) and 3.58 (2.94 to 4.36), respectively. By probit regression the absolute increase in risk of death at 1 year associated with receiving a transfusion was 6.78%. The number needed to treat was 14.74 (prevention of 15 transfusions required to "avoid" one death). Radial access halved the transfusion rate. After adjustment for all variables, radial access was associated with a significant reduction in 30-day and 1-year mortality, odds ratio = 0.71 (95% CI 0.61 to 0.82) and 0.83 (0.71 to 0.98), respectively (all p<0.001).

CONCLUSIONS

In a registry of all comers to PCI, transradial access was associated with a halving of the transfusion rate and a reduction in 30-day and 1-year mortality.

Targeting FGFR3 in multiple myeloma: inhibition of t(4;14)-positive cells by SU5402 and PD173074

The t(4;14)(p16.3;q32), associated with 10-20% of cases of multiple myeloma (MM), deregulates the expression of MMSET and FGFR3. To assess the potential of FGFR3 as a drug target, we evaluated the effects of selective inhibitors on MM and control cell lines. SU5402 and PD173074 specifically inhibited the growth of the two t(4;14)-positive MM lines, KMS-11 and OPM-2. Importantly, inhibition was still observed in the presence of IL-6, a growth factor known to play an important role in MM. Both compounds induced a dose-dependent reduction in cell viability and an increase in apoptosis, accompanied by a decrease in extracellular signal-related kinase phosphorylation. In contrast, no inhibition was seen with either compound against t(4;14)-negative cell lines or NCI-H929, a t(4;14)-positive, FGFR3-negative MM cell line. FGFR3 is thus a plausible candidate for targeted therapy in a subset of MM patients.

P2X7 polymorphism and chronic lymphocytic leukaemia: lack of correlation with incidence, survival and abnormalities of chromosome 12

The P2X7 receptor, a plasma membrane ATP-gated ion channel that plays a role in lymphocyte apoptosis, has been suggested as an important contributory factor to the pathogenesis of chronic lymphocytic leukaemia (CLL). The P2X7 gene resides on chromosome 12 and is polymorphic in the population at large (1513A/C) with the A and C alleles encoding fully active and nonfunctional proteins, respectively. We have evaluated the significance of this polymorphism by genotyping 144 patients with CLL and 348 healthy controls using a tetraprimer ARMS assay. We found no significant difference in allele frequency between patients and controls. Although patients with the C allele (A/C heterozygotes or C/C homozygotes) had a marginally shorter survival than those who were homozygous for the A allele, this difference was not significant for either the patient group considered as a whole or for IgVH-mutated/unmutated subsets. Finally, no association was found between trisomy 12 and P2X7 genotype. We conclude that the influence, if any, of P2X7 genotype on susceptibility to CLL or clinical outcome is small.

Role of nuclear factor-kappa B activation in metalloproteinase-1, -3, and -9 secretion by human macrophages in vitro and rabbit foam cells produced in vivo

Metalloproteinase secretion by macrophages is believed to play a key role in the matrix degradation that underlies atherosclerotic plaque instability and aneurysm formation. We studied the hypothesis that nuclear factor-kappaB (NF-kappaB), a transcription factor, is necessary for metalloproteinase secretion and, hence, is a target for pharmacological intervention. Adenovirus-mediated gene transfer of the inhibitory NF-kappaB subunit, I-kappa Balpha, was achieved into human monocyte-derived macrophages in vitro and into foam cells produced in vivo in cholesterol-fed rabbits. Human macrophages and rabbit foam cells secreted matrix-degrading metalloproteinase (MMP)-9 without further stimulation, and this was not inhibited by I-kappaBalpha (11+/-16% and 8+/-10%, respectively; P> 0.05). MMP-1 secretion from human macrophages increased in response to recombinant human CD40 ligand and was inhibited 92+/-5% by I-kappaBalpha (n=3, P<0.05). Rabbit foam cells secreted MMP-1 and -3 without further stimulation, and this was inhibited 83+/-12% and 69+/-11%, respectively, by I-kappaBalpha (n=6 or 7, P<0.001). I-kappaBalpha did not significantly affect the expression or activity of tissue inhibitor of metalloproteinases-1 or -2. Overexpression of I-kappaBalpha inhibited collagenolytic and beta-caseinolytic activity by 42+/-2% and 41+/-7%, respectively (n=3, P<0.05). Secretion of MMP-1 and MMP-3 from macrophages stimulated in vitro or in vivo depends on the activation of NF-kappaB. Because the inhibition of NF-kappaB reduces proteolytic activity, it appears to be an attractive pharmacological target in unstable atheromas.

Inhibition of transcription factor NF-κB reduces matrix metalloproteinase-1, -3 and -9 production by vascular smooth muscle cells

OBJECTIVE

Matrix metalloproteinases (MMPs) contribute to the destruction of the extracellular matrix at the shoulder regions of atherosclerotic plaques that leads to plaque destabilisation and triggers clinical cardiovascular disease. There is therefore considerable interest in establishing the mechanisms responsible for increased MMP production. MMPs-1, -3 and -9 are upregulated by inflammatory cytokines and growth factors that are produced by plaque resident macrophages and smooth muscle cells. Our present studies focused on NF-kappaB, which regulates numerous inflammatory genes, and is activated in plaque smooth muscle cells. Moreover, an NF-kappaB binding site is present in the promoter of the MMP-9 gene and an NF-kappaB-like element in the promoter of the MMP-1 gene.

METHODS

We used adenovirus mediated overexpression of its inhibitor, I kappaBalpha to investigate the role of NF-kappaB in regulation of MMP-1, -3 and -9 by isolated, cytokine stimulated rabbit aortic and human saphenous vein VSMC.

RESULTS

IL-1alpha potently activated NF-kappa B in VSMCs and acted synergistically with growth factors to upregulate expression of MMP-1, -3 and -9. Overexpression of I kappaBalpha, almost completely inhibited expression of MMP-1, -3 and -9 in response to IL-1alpha alone or in combination with bFGF and PDGF.

CONCLUSION

NF-kappaB is required for cytokine upregulation of MMP-1, -3 and -9 in VSMCs, which suggests that NF-kappaB inhibition may promote plaque stabilisation.