Long-term durability of self-expanding and balloon-expandable transcatheter aortic valve prostheses: UK TAVI registry.

BACKGROUND: With expansion of transcatheter aortic valve implantation (TAVI) into younger patients, valve durability is critically important. AIMS: We aimed to evaluate long-term valve function and incidence of severe structural valve deterioration (SVD) among patients ≥ 10-years post-TAVI and with echocardiographic follow-up at least 5-years postprocedure. METHODS: Data on patients who underwent TAVI from 2007 to 2011 were obtained from the UK TAVI registry. Patients with paired echocardiograms postprocedure and ≥5-years post-TAVI were included. Severe SVD was determined according to European task force guidelines. RESULTS: 221 patients (79.4 ± 7.3 years; 53% male) were included with median echocardiographic follow-up 7.0 years (range 5-13 years). Follow-up exceeded 10 years in 43 patients (19.5%). Valve types were the supra-annular self-expanding CoreValve (SEV; n = 143, 67%), balloon-expandable SAPIEN/XT (BEV; n = 67, 31%), Portico (n = 4, 5%) and unknown (n = 7, 3%). There was no difference between postprocedure and follow-up peak gradient in the overall cohort (19.3 vs. 18.4 mmHg; p = NS) or in those with ≥10-years follow-up (21.1 vs. 21.1 mmHg; p = NS). Severe SVD occurred in 13 patients (5.9%; median 7.8-years post-TAVI). Three cases (23.1%) were due to regurgitation and 10 (76.9%) to stenosis. Valve-related reintervention/death occurred in 5 patients (2.3%). Severe SVD was more frequent with BEV than SEV (11.9% vs. 3.5%; p = 0.02), driven by a difference in patients treated with small valves (BEV 28.6% vs. SEV 3.0%; p < 0.01). CONCLUSIONS: Hemodynamic function of transcatheter heart valves remains stable up to more than 10 years post-TAVI. Severe SVD occurred in 5.9%, and valve-related death/reintervention in 2.3%. Severe SVD was more common with BEV than SEV.

Safety and efficacy of interrupting dual antiplatelet therapy one month following percutaneous coronary intervention: a meta-analysis of randomized controlled trials.

Very short duration of dual antiplatelet therapy (DAPT) following percutaneous coronary intervention (PCI) has recently attracted a lot of attention with the introduction of newer generations stents. This is appealing, especially in patients at high bleeding risk. However, none of the trials were powered for the individual ischemic and bleeding endpoints. All randomised controlled trials (RCTs) investigating one-month versus routine duration of DAPT in patients undergoing PCI and reporting outcomes from the time of cessation of DAPT (1 month) to 1 year were eligible for inclusion in the meta-analysis. The pooled risk ratios (RR) with their 95% confidence interval (CI) were calculated with the random-effects model using the Mantel-Haenszel method. Four RCTs involving 26,576 patients were included in this meta-analysis. Cessation of DAPT after 1 month was associated with significantly less major bleeding [RR 0.70, 95%CI (0.51-0.95), P = 0.02, heterogeneity (I2) = 42%]. There was no statistically significant difference in all-cause mortality [RR 0.84 (95%CI 0.69-1.03), P = 0.10, I2 = 0%] and stroke [RR 0.71 (95%CI 0.45-1.13), P = 0.15, I2 = 42%] when compared to routine duration of DAPT. There was also no difference in myocardial infarction (MI) [RR 1.12 (95%CI 0.91-1.39), P = 0.28, I2 = 0%], and definite or probable stent thrombosis [RR 1.49 (95%CI 0.92-2.41), P = 0.11, I2 = 0%] with cessation of DAPT after 1 month. Cessation of DAPT 1 month after PCI was associated with significantly less major bleeding, but there was no difference in the rate of all-cause mortality, stroke, MI and stent thrombosis.

Rationale and Design of the Project to Look for Early Discharge in Patients Undergoing TAVR With ACURATE (POLESTAR Trial).

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is now an established treatment strategy for elderly patients with symptomatic aortic stenosis (AS) across the entire operative risk spectrum. Streamlined TAVR protocols along with reduced procedure time and expedited ambulation promote early hospital discharge. Selection of patients suitable for safe early discharge after TAVR might improve healthcare efficiency. STUDY DESIGN: The POLESTAR trial is an international, multi-center, prospective, observational study which aims to evaluate the safety of early discharge in selected patients who undergo TAVR with the supra-annular functioning self-expanding ACURATE Neo transcatheter heart valve (THV). A total of 250 patients will be included based on a set of baseline criteria indicating potential early discharge (within 48 h post-TAVR). Primary study endpoints include Valve Academic Research Consortium (VARC)-3 defined safety at 30 days and VARC-3 defined efficacy at 30 days and 1 year. Endpoints will be compared between early discharge and non-early discharge cohorts with a distinct landmark analysis at 48 h post-TAVR. Secondary endpoints include quality of life assessed using EQ5D-5L and Kansas City Cardiomyopathy Questionnaire (KCCQ) questionnaires and resource costs compared between discharge groups. SUMMARY: The POLESTAR trial prospectively evaluates safety and feasibility of an early discharge protocol for TAVR using the ACURATE Neo THV.

A cohort study examining urgent and emergency treatment for decompensated severe aortic stenosis.

AIMS: We compared strategies in the treatment of decompensated severe aortic stenosis. The hypothesis was that undertaking urgent or emergency transcatheter aortic valve implantation (TAVI) directly in such patients is safer and more effective than urgent or emergency balloon aortic valvuloplasty (BAV) followed by elective TAVI or surgical aortic valve replacement (SAVR). METHODS: This was a single-centre retrospective study including all consecutive patients who underwent urgent or emergency BAV or TAVI for decompensated severe aortic stenosis between September 2014 and February 2018. Primary endpoints were 30-day and 1-year mortality. RESULTS: Fifty-two patients underwent urgent or emergency BAV and 87 underwent TAVI. Baseline characteristics of the two groups were well matched. Significant differences were noted between the two groups in 30-day all-cause mortality (88.5% BAV patients alive at 30 days, 97.7% TAVI patients; P < 0.05) and 1-year all-cause mortality (44.2% BAV patients alive at 1 year, 88.5% TAVI patients; P < 0.001). At 1 year, the estimated hazard ratio for patients undergoing BAV was 11.2 (95% confidence interval: 4.67-26.9; P < 0.001) when adjusted for potential confounding variables. Patients in the BAV group who successfully underwent subsequent TAVI or SAVR all survived for 365 days, but there was no significant 1-year mortality difference compared with those who underwent urgent or emergency TAVI (100 vs. 88.5%; P > 0.155). CONCLUSION: Our results suggest treatment of decompensated severe aortic stenosis with urgent or emergency TAVI may be associated with improved survival outcomes when compared with a strategy of performing BAV as a bridge to subsequent TAVI or SAVR.

Untreatable Severe Structural Degeneration of a Transcatheter Aortic Heart Valve.

We describe a patient who presented with heart failure 7 years post-transcatheter aortic valve implantation (TAVI) as a result of severe structural valve degeneration. Anatomic challenges, combined with the type of transcatheter heart valve used initially, meant that TAVI-in-TAVI risked obstructing the coronary arteries, even if preceded by bioprosthetic aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction. The patient was treated with balloon aortic valvuloplasty.

Initial experience of a self-expanding transcatheter aortic valve with an outer pericardial wrap: The United Kingdom and Ireland Implanters' registry.

OBJECTIVES: The United Kingdom and Ireland Implanters' registry is a multicenter registry which reports on real-world experience with new transcatheter heart valves. BACKGROUND: The Evolut PRO (Medtronic, Minneapolis, MN) transcatheter aortic valve is a self-expanding transcatheter aortic valve with an outer pericardial wrap, designed to minimize paravalvular regurgitation. METHODS: Between July 2017 and December 2018, clinical, procedural, and 30-day outcome data were prospectively collected from all patients receiving the Evolut PRO valve across nine participating centers in the United Kingdom and Ireland. The primary efficacy outcome was the Valve Academic Research Consortium-2 (VARC-2)-defined endpoint of device success. The primary safety outcome was the VARC-2-defined composite endpoint of early safety at 30 days. RESULTS: A total of 317 patients underwent implantation. Mean age was 81.8 ± 6.4 years and Society of Thoracic Surgeons Predicted Risk of Mortality Score 5.5 ± 1.8%. Iliofemoral access was used in 99.1% of patients. Device success was 91.2%. Mean gradient was 7.6 ± 4.7 mmHg and effective orifice area 1.9 ± 0.7 cm2 . The incidence of moderate paravalvular regurgitation was 1.7% and there was no severe paravalvular regurgitation. A new permanent pacemaker was implanted in 17.8% of patients without a pacemaker at baseline. Early safety was demonstrated in 92.7%. At 30 days, all-cause mortality was 0.6%, stroke 3.8%, and major vascular complication 2.8%. CONCLUSIONS: Real-world experience of the Evolut PRO transcatheter aortic valve demonstrated favorable procedural success, safety, valve function, and incidence of new permanent pacemaker implantation.

Long-Term Durability of Transcatheter Aortic Valve Prostheses.

BACKGROUND: Very little is known about long-term valve durability after transcatheter aortic valve replacement (TAVR). OBJECTIVES: This study sought to evaluate the incidence of structural valve degeneration (SVD) 5 to 10 years post-procedure. METHODS: Demographic, procedural, and in-hospital outcome data on patients who underwent TAVR from 2007 to 2011 were obtained from the U.K. TAVI (United Kingdom Transcatheter Aortic Valve Implantation) registry. Patients in whom echocardiographic data were available both at baseline and ≥5 years post-TAVR were included. Hemodynamic SVD was determined according to European task force committee guidelines. RESULTS: A total of 241 patients (79.3 ± 7.5 years of age; 46% female) with paired post-procedure and late echocardiographic follow-up (median 5.8 years, range 5 to 10 years) were included. A total of 149 patients (64%) were treated with a self-expandable valve and 80 (34.7%) with a balloon-expandable valve. Peak aortic valve gradient at follow-up was lower than post-procedure (17.1 vs. 19.1 mm Hg; p = 0.002). More patients had none/trivial aortic regurgitation (AR) (47.5% vs. 33%), and fewer had mild AR (42.5% vs. 57%) at follow-up (p = 0.02). There was 1 case (0.4%) of severe SVD 5.3 years after implantation (new severe AR). There were 21 cases (8.7%) of moderate SVD (mean 6.1 years post-implantation; range 4.9 to 8.6 years). Twelve of these (57%) were due to new AR and 9 (43%) to restenosis. CONCLUSIONS: Long-term transcatheter aortic valve function is excellent. In the authors' study, 91% of patients remained free of SVD between 5 and 10 years post-implantation. The incidence of severe SVD was <1%. Moderate SVD occurred in 1 in 12 patients.

Initial experience of a large, self-expanding, and fully recapturable transcatheter aortic valve: The UK & Ireland Implanters' registry.

OBJECTIVES: The UK & Ireland Implanters' registry is a multicenter registry which reports on real-world experience with novel transcatheter heart valves. BACKGROUND: The 34 mm Evolut R transcatheter aortic valve is a self-expanding and fully recapturable transcatheter aortic valve, designed to treat patients with a large aortic annulus. METHODS: Between January 2017 and April 2018, clinical, procedural and 30-day outcome data were prospectively collected from all patients receiving the 34 mm Evolut R valve across 17 participating centers in the United Kingdom and Ireland. The primary efficacy outcome was the Valve Academic Research Consortium-2(VARC-2)-defined endpoint of device success. The primary safety outcome was the VARC-2-defined composite endpoint of early safety at 30 days. RESULTS: A total of 217 patients underwent attempted implant. Mean age was 79.5 ± 8.8 years and Society of Thoracic Surgeons Predicted Risk of Mortality Score 5.2% ± 3.4%. Iliofemoral access was used in 91.2% of patients. Device success was 79.7%. Mean gradient was 7.0 ± 4.6 mmHg and effective orifice area 2.0 ± 0.6 cm2 . Paravalvular regurgitation was more than mild in 7.2%. A new permanent pacemaker was implanted in 15.7%. Early safety was demonstrated in 91.2%. At 30 days, all-cause mortality was 3.2%, stroke 3.7%, and major vascular complication 2.3%. CONCLUSIONS: Real-world experience of the 34 mm Evolut R transcatheter aortic valve demonstrated acceptable procedural success, safety, valve function, and incidence of new permanent pacemaker implantation.

Cardiogoniometry Compared to Fractional Flow Reserve at Identifying Physiologically Significant Coronary Stenosis: The CARDIOFLOW Study.

Cardiogoniometry (CGM) is method of 3-dimensional electrocardiographic assessment which has been shown to identify patients with angiographically defined, stable coronary artery disease (CAD). However, angiographic evidence of CAD, does not always correlate to physiologically significant disease. The aim of our study was to assess the ability of CGM to detect physiologically significant coronary stenosis defined by fractional flow reserve (FFR). In a tertiary cardiology centre, elective patients with single vessel CAD were enrolled into a prospective double blinded observational study. A baseline CGM recording was performed at rest. A second CGM recording was performed during the FFR procedure, at the time of adenosine induced maximal hyperaemia. A significant CGM result was defined as an automatically calculated ischaemia score < 0 and a significant FFR ratio was defined as < 0.80. Measures of diagnostic performance (including sensitivity and specificity) were calculated for CGM at rest and during maximal hyperaemia. Forty-five patients were included (aged 61.1 ± 11.0; 60.0% male), of which eighteen (40%) were found to have significant CAD when assessed by FFR. At rest, CGM yielded a sensitivity of 33.3% and specificity of 63.0%. At maximal hyperaemia the sensitivity and specificity of CGM was 71.4 and 50.0% respectively. The diagnostic performance of CGM to detect physiologically significant stable CAD is poor at rest. Although, the diagnostic performance of CGM improves substantially during maximal hyperaemia, it does not reach sufficient levels of accuracy to be used routinely in clinical practice.

Biomarkers of coronary endothelial health: correlation with invasive measures of collateral function, flow and resistance in chronically occluded coronary arteries and the effect of recanalization.

OBJECTIVES: In the presence of a chronically occluded coronary artery, the collateral circulation matures by a process of arteriogenesis; however, there is considerable variation between individuals in the functional capacity of that collateral network. This could be explained by differences in endothelial health and function. We aimed to examine the relationship between the functional extent of collateralization and levels of biomarkers that have been shown to relate to endothelial health. METHODS: We measured four potential biomarkers of endothelial health in 34 patients with mature collateral networks who underwent a successful percutaneous coronary intervention (PCI) for a chronic total coronary occlusion (CTO) before PCI and 6-8 weeks after PCI, and examined the relationship of biomarker levels with physiological measures of collateralization. RESULTS: We did not find a significant change in the systemic levels of sICAM-1, sE-selectin, microparticles or tissue factor 6-8 weeks after PCI. We did find an association between estimated retrograde collateral flow before CTO recanalization and lower levels of sICAM-1 (r=0.39, P=0.026), sE-selectin (r=0.48, P=0.005) and microparticles (r=0.38, P=0.03). CONCLUSION: Recanalization of a CTO and resultant regression of a mature collateral circulation do not alter systemic levels of sICAM-1, sE-selectin, microparticles or tissue factor. The identified relationship of retrograde collateral flow with sICAM-1, sE-selectin and microparticles is likely to represent an association with an ability to develop collaterals rather than their presence and extent.

Microvascular dysfunction in the immediate aftermath of chronic total coronary occlusion recanalization.

OBJECTIVES: The aim of this study was to compare microvascular resistance under both baseline and hyperemic conditions immediately after percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) with an unobstructed reference vessel in the same patient BACKGROUND: Microvascular dysfunction has been reported to be prevalent immediately after CTO PCI. However, previous studies have not made comparison with a reference vessel. Patients with a CTO may have global microvascular and/or endothelial dysfunction, making comparison with established normal values misleading. METHODS: After successful CTO PCI in 21 consecutive patients, coronary pressure and flow velocity were measured at baseline and hyperemia in distal segments of the CTO/target vessel and an unobstructed reference vessel. Hemodynamics including hyperemic microvascular resistance (HMR), basal microvascular resistance (BMR), and instantaneous minimal microvascular resistance at baseline and hyperemia were calculated and compared between reference and target/CTO vessels. RESULTS: After CTO PCI, BMR was reduced in the target/CTO vessel compared with the reference vessel: 3.58 mm Hg/cm/s vs 4.94 mm Hg/cm/s, difference -1.36 mm Hg/cm/s (-2.33 to -0.39, p = 0.008). We did not detect a difference in HMR: 1.82 mm Hg/cm/s vs 2.01 mm Hg/cm/s, difference -0.20 (-0.78 to 0.39, p = 0.49). Instantaneous minimal microvascular resistance correlated strongly with the length of stented segment at baseline (r = 0.63, p = 0.005) and hyperemia (r = 0.68, p = 0.002). CONCLUSIONS: BMR is reduced in a recanalized CTO in the immediate aftermath of PCI compared to an unobstructed reference vessel; however, HMR appears to be preserved. A longer stented segment is associated with increased microvascular resistance. © 2016 Wiley Periodicals, Inc.

Collateral donor artery physiology and the influence of a chronic total occlusion on fractional flow reserve.

BACKGROUND: The presence of a concomitant chronic total coronary occlusion (CTO) and a large collateral contribution might alter the fractional flow reserve (FFR) of an interrogated vessel, rendering the FFR unreliable at predicting ischemia should the CTO vessel be revascularized and potentially affecting the decision on optimal revascularization strategy. We tested the hypothesis that donor vessel FFR would significantly change after percutaneous coronary intervention of a concomitant CTO. METHODS AND RESULTS: In consecutive patients undergoing percutaneous coronary intervention of a CTO, coronary pressure and flow velocity were measured at baseline and hyperemia in proximal and distal segments of both nontarget vessels, before and after percutaneous coronary intervention. Hemodynamics including FFR, absolute coronary flow, and the coronary flow velocity-pressure gradient relation were calculated. After successful percutaneous coronary intervention in 34 of 46 patients, FFR in the predominant donor vessel increased from 0.782 to 0.810 (difference, 0.028 [0.012 to 0.044]; P=0.001). Mean decrease in baseline donor vessel absolute flow adjusted for rate pressure product: 177.5 to 139.9 mL/min (difference -37.6 [-62.6 to -12.6]; P=0.005), mean decrease in hyperemic flow: 306.5 to 272.9 mL/min (difference, -33.5 [-58.7 to -8.3]; P=0.011). Change in predominant donor vessel FFR correlated with angiographic (%) diameter stenosis severity (r=0.44; P=0.009) and was strongly related to stenosis severity measured by the coronary flow velocity-pressure gradient relation (r=0.69; P<0.001). CONCLUSIONS: Recanalization of a CTO results in a modest increase in the FFR of the predominant collateral donor vessel associated with a reduction in coronary flow. A larger increase in FFR is associated with greater coronary stenosis severity.

Chromosome 16q22 variants in a region associated with cardiovascular phenotypes correlate with ZFHX3 expression in a transcript-specific manner.

BACKGROUND: The ZFHX3 gene, located in Chromosome 16q22.3, codes for a transcription factor which is widely expressed in human tissues. Genome-wide studies have identified associations between variants within the gene and Kawasaki disease and atrial fibrillation. ZFHX3 has two main transcripts that utilise different transcription start sites. We examined the association between genetic variants in the 16q22.3 region and expression of ZFHX3 to identify variants that regulate gene expression. RESULTS: We genotyped 65 single-nucleotide polymorphisms to tag genetic variation at the ZFHX3 locus in two cohorts, 451 British individuals recruited in the North East of England and 310 mixed-ancestry individuals recruited in South Africa. Allelic expression analysis revealed that the minor (A) allele of rs8060701, a variant in the first intron of ZFHX3, was associated with a 1.16-fold decrease in allelic expression of both transcripts together, (p = 4.87e-06). The minor (C) allele of a transcribed variant, rs10852515, in the second exon of ZFHX3 isoform A was independently associated with a 1.36-fold decrease in allelic expression of ZFHX3 A (p = 7.06e-31), but not overall ZFHX3 expression. However, analysis of total gene expression of ZFHX3 failed to detect an association with genotype at any variant. Differences in linkage disequilibrium between the two populations allowed fine-mapping of the locus to a 7 kb region overlapping exon 2 of ZFHX3 A. We did not find any association between ZFHX3 expression and any of the variants identified by genome wide association studies. CONCLUSIONS: ZFHX3 transcription is regulated in a transcript-specific fashion by independent cis-acting transcribed polymorphisms. Our results demonstrate the power of allelic expression analysis and trans-ethnic fine mapping to identify transcript-specific cis-acting regulatory elements.

Relationship of aortic annular eccentricity and paravalvular regurgitation post transcatheter aortic valve implantation with CoreValve.

BACKGROUND: Significant paravalvular aortic regurgitation (PAR) after transcatheter aortic valve implantation (TAVI) is associated with negative clinical consequences. We hypothesize that increased eccentricity of the aortic annulus is associated with greater PAR. METHODS: Patients with severe aortic stenosis underwent multidetector computed tomography (MDCT) before successful TAVI with the Medtronic CoreValve bioprosthesis. The smallest (D(min)) and largest (D(max)) orthogonal diameters in the basal ring of the aortic annulus were determined. We defined circularity of aortic annulus using the eccentricity index (1 - D(min)/D(max)). The primary endpoint was early occurrence of significant PAR, defined as > grade II PAR by postprocedural aortography. RESULTS: Eighty-four patients, mean age 83 ± 4 years with a mean aortic valve area of 0.7 ± 0.2 cm² were included. Twenty patients had postprocedural PAR > grade II. Using a receiver operating characteristic (ROC) analysis, eccentricity index correlated with significant PAR (AUC = 0.834; P=.034). A retrospectively determined eccentricity index cut-off of >0.25 was related to significant PAR with a sensitivity of 80%, specificity of 86%, and negative predictive value of 95% (P<.001). On univariate logistic regression, eccentricity index of >0.25 (P<.001) and device implantation depth (P=.015) correlated with significant PAR, while other parameters such as annular calcification and cover index did not. On multivariate analysis including only parameters with P<.1 on univariate analysis, eccentricity index >0.25 was the sole independent predictor of significant PAR. CONCLUSION: Eccentricity index is related to significant PAR after TAVI with Medtronic CoreValve. Further larger studies are required to determine the utility of this novel index in screening suitable patients for this procedure.

Prognostic value of adenosine stress perfusion cardiac MRI with late gadolinium enhancement in an intermediate cardiovascular risk population.

BACKGROUND: The high diagnostic accuracy of adenosine stress cardiac magnetic resonance (AS-CMR) for detecting coronary artery stenoses, with high sensitivity and specificity, is well documented. Prognostic data, particularly in non-low risk study populations and for greater than 12 months of follow up, is however lacking or variable in its findings. We present prognostic data, in an intermediate cardiovascular risk cohort undergoing adenosine stress perfusion CMR, over approximately 2 years of follow up. METHODS: The study population comprised 362 patients referred for a clinically indicated stress CMR and included patients with proven coronary artery disease (CAD; n=157) or unknown CAD status, yet an intermediate cardiovascular risk profile (n=205). Perfusion imaging was performed at stress (adenosine 140 µg/kg/min) and rest on a 1.5 T system. Patient records and state-wide hospital databases were reviewed. Major adverse cardiac events--death, myocardial infarction, revascularisation or ischaemic hospitalisation--were evaluated over a median follow up of 22 months. RESULTS: Of the 362 cases, 90 had a stress perfusion CMR positive for ischaemia and experienced a MACE rate of 24%. Of the 272 negative CMR scans, 225 were also negative for late gadolinium enhancement, and in this group MACE was encountered in only 6 (2.7%) patients. Accordingly a negative stress CMR afforded a freedom from MACE of 97.3%. Freedom from death/myocardial infarction was 99.6%. CONCLUSIONS: In patients with confirmed coronary artery disease or at intermediate risk for cardiovascular events, a negative stress perfusion CMR is associated with an excellent prognosis over nearly 2 years of follow up.

Aortic annulus dimension assessment by computed tomography for transcatheter aortic valve implantation: differences between systole and diastole.

Accurate assessment of aortic annular dimensions is essential for successful transcatheter aortic valve implantation (TAVI). Annular dimensions are conventionally measured in mid-systole by multidetector computed tomography (MDCT), echocardiography and angiography. Significant differences in systolic and diastolic aortic annular dimensions have been demonstrated in cohorts without aortic stenosis (AS), but it is unknown whether similar dynamic variation in annular dimensions exists in patients with severe calcific AS in whom aortic compliance is likely to be substantially reduced. We investigated the variation in aortic annular dimensions between systole and diastole in patients with severe calcific AS. Patients with severe calcific AS referred for TAVI were evaluated by 128-slice MDCT. Aortic annular diameter was measured during diastole and systole in the modified coronal, modified sagittal, and basal ring planes (maximal, minimal and mean diameters). Differences between systole and diastole were analysed by paired t test. Fifty-nine patients were included in the analysis. Three of the five aortic dimensions measured increased significantly during systole. The largest change was a 0.75 mm (3.4%) mean increase in the minimal diameter of the basal ring during systole (p = 0.004). This corresponds closely to the modified sagittal view, which also increased by mean 0.42 mm (1.9%) during systole (p = 0.008). There was no significant change in the maximal diameter of the basal ring or the modified coronal view during systole (p > 0.05). There is a small magnitude but statistically significant difference in aortic annulus dimensions of patients with severe AS referred for TAVI when measured in diastole and systole. This small difference is unlikely to alter clinical decisions regarding prosthesis size or suitability for TAVI.

Genetic mechanisms mediating atherosclerosis susceptibility at the chromosome 9p21 locus.

Recent genome-wide association studies have demonstrated that common genetic variants in a region of chromosome 9p21 confer risk of coronary artery disease (CAD) and other atherosclerotic conditions. Although the absolute increase in risk is small (some 20-30% increase in risk of CAD per copy of the deleterious alleles), the common occurrence of the variants means that their effect on the population risk of disease is estimated to be substantial. Studies investigating the relationship between risk variants and both "classical" and "emerging" atherosclerotic risk factors have found no evidence of association. This suggests that the effect of the 9p21 locus on atherosclerotic risk is mediated via a hitherto unknown pathway potentially amenable to therapeutic modulation. Investigation of potential disease mechanisms at this locus is therefore a focus of intense interest. In this review, we discuss the progress that has been made in the study of mechanisms and highlight the outstanding research questions.

MLH1 Differential allelic expression in mutation carriers and controls.

Germline defects in the MLH1 gene are associated with Lynch syndrome. A substantial proportion of these mutations leads to premature termination codons and can induce nonsense mediated decay (NMD) of the corresponding transcript. Resulting allelic expression differences represent a fast and inexpensive method to identify patients carrying MLH1 mutations. In patients and controls, we show that allelic expression imbalance (AEI) can be readily detected in RNA extracted from whole blood from patients carrying mutations expected to elicit NMD using mass spectrometry. Mutations closer to the 5' end of the gene tend to show smaller imbalances. AEI can also be detected in normal controls. Analysis of allelic expression in controls and individuals with mutations not expected to exhibit NMD revealed that MLH1 expression is influenced by sequence variation acting in cis. A maximum likelihood framework was used to identify two SNPs, rs1799977 (c.655G>A; p.I219V) and rs1800734 (c.-93 G>A) that are independently associated with expression. These influences are, however, small compared to the differences associated with pathological variants.