Interaction of stroke volume and myocardial phenotype in patients with severe aortic stenosis referred for intervention: outcome data from the BSCMR AS700 study

Funding Acknowledgements

Type of funding sources: None.

onbehalf

The BSCMR Valve Consortium

Background

 Patients with low-flow aortic stenosis (LF-AS) have higher mortality than those with high-flow severe AS.  The conventional echocardiographic definition of LF-AS is an indexed stroke volume (SVi) <35ml/m2. Whether this cut-off translates to cardiac magnetic resonance (CMR), and how CMR SVi associates with myocardial remodelling (volume/function/scar) and survival is unclear.

Purpose

 To determine the association between CMR SVi, myocardial remodelling and survival in severe symptomatic AS. 

Methods

  In a multi-centre longitudinal outcome study of patients with severe AS listed for either surgical (SAVR) or transcatheter aortic valve intervention (TAVI) at six cardiothoracic centres, survival was assessed and stratified by SVi. Patients underwent preprocedural echocardiography and CMR between January 2003 and May 2015.  Standardised core-lab analyses on pre-procedural CMR for biventricular volumes, function and scar quantification were performed. All-cause and cardiovascular mortality were tracked for a minimum of two years after AVR.

Results

 A total of 674 patients with severe AS (age 75 ± 14years; 63% male, aortic valve area 0.4 ± 0.1 cm2/m2) were included.  Patients with low SVi by CMR <35ml/m2 were older and had a greater burden of comorbidities (atrial fibrillation [AF], diabetes, high BMI). Independent predictors of SVi were age, AF, increased left atrial volume, aortic valve regurgitant fraction and left ventricular mass (LV) mass index (by CMR). There was no difference in SVi with choice of intervention (TAVI vs SAVR) or presence of late gadolinium enhancement. In multivariate analysis (Table 1), SVi was associated with cardiovascular mortality in the whole cohort (HR 0.97, 95%CI 0.95-0.99, p = 0.02), and all-cause mortality after TAVI (HR 0.97, 95%CI 0.95-0.99, p = 0.006) but not SAVR (p = 0.6). Adjusted mortality hazard increases below 50ml/m2 and plateaus between 35-40ml/m2 (Figure 1A), adjusted for LGE, STS score (Society of Thoracic Surgery score) and wall thickness.

Conclusion

SVi by CMR is an independent predictor of cardiovascular mortality. Mortality hazard increases progressively below a SVi of 50mL/m2.

Abstract Figure 1

480Right ventricular dysfunction is associated with late mortality in severe aortic stenosis: results from a multi-centre outcome study in patients undergoing aortic valve replacement

Background

The right ventricle (RV) is relatively understudied and often not routinely assessed in aortic stenosis (AS). However, there are several potential reasons for its importance. RV function is sensitive to left-sided afterload changes which can result in pulmonary hypertension (PH) in severe AS. PH is also a recognised predictor of poor prognosis in AS, but RV afterload and function can be difficult to assess. Cardiovascular magnetic resonance (CMR) may reveal unrecognised RV dysfunction and simultaneously evaluate other prognostic markers in AS.

Purpose

To investigate preoperative RV function assessed by CMR in severe AS and its association with mortality after aortic valve replacement (AVR).

Methods

674 severe AS patients listed for either surgical or percutaneous AVR at six cardiothoracic centres underwent preoperative CMR (for ventricular function, mass and scar) along with echocardiography for valve severity. Scans were core-lab analysed for LV and RV volumes, function and scar quantification. Eight patients were excluded due to inadequate RV image quality for a total of 666 patients finally included. All-cause mortality was tracked for a minimum of 2 years after AVR.

Results

107 (16%) of severe AS undergoing invasive AVR had a RV ejection fraction (RVEF) <55%. CMR detected overt RV dysfunction (RVEF <50%) in 61 (9%) patients. During a median 3.6 years follow-up, 145 (22%) patients died. Baseline RV dysfunction was the most powerful predictor of all-cause mortality (hazard ratio [HR] 2.5, 95% CI 1.6–3.9, p<0.0001). RV function was independent from other clinical characteristics but associated with signs of LV maladaptation (LV ejection fraction [LVEF] and late gadolinium enhancement [LGE]). The strongest Cox multivariable model for all-cause mortality accounted for RV dysfunction, age and LGE (adjusted HRs 1.7, 1.1, 2.2, respectively). Even early stages of pre-procedural RV dysfunction (RVEF 45–50%) were associated with reduced long-term survival.

Cox and Kaplan-Meier for all-cause death

Conclusion

One out of 6 patients with severe AS undergoing valve replacement manifests a reduction in RV function detectable by CMR. Those with RV dysfunction (RVEF<50%) have a 2.5-fold increase in all-cause mortality after AVR at 3.6 years. Whilst RV dysfunction is associated with LV maladaptation (LGE, LVEF), it is a powerful independent factor associated with all-cause mortality and impacts survival even at early stages. Thus, the RV appears to be important in cardiac adaptation to AS and longevity after AS intervention.

Acknowledgement/Funding

British Heart Foundation and National Institute of Health Research

Economic evaluation of the treatment of grade II haemorrhoids: a comparison of stapled haemorrhoidopexy and rubber band ligation

OBJECTIVES

Haemorrhoidal disease is a common condition causing considerable distress to individuals and significant cost to healthcare services. This paper explored the cost-effectiveness of stapled haemorrhoidopexy (SH) compared with the non-surgical intervention, rubber band ligation (RBL), for grade II symptomatic circumferential haemorrhoids.

METHOD

An economic evaluation alongside a randomized controlled trial conducted between October 2002 and February 2005. Adults were recruited and randomized to either SH or RBL. The same surgeon performed all procedures and investigators were blinded until analyses were completed. Primary outcomes measured at 52 weeks were cumulative costs to the NHS, clinical diagnosis of recurrence and quality adjusted life years (QALYs).

RESULTS

Sixty symptomatic men and women with confirmed clinical diagnosis of grade II symptomatic haemorrhoids were randomized. Loss to follow-up was up to 10% at 52 weeks. The mean cost for SH was greater than RBL (mean difference: 1483 pounds, 95% CI: 1339-1676); disease recurrence was lower (OR = 0.18, 95% CI: 0.03-0.86); and there was no evidence of a statistically significant difference in QALYs (-0.014, 95% CI: -0.076 to 0.051). SH was associated with a modest incremental cost per recurrence avoided at 12 months follow-up (4945 pounds). Based on current data, it was considered highly unlikely to be cost-effective in terms of incremental cost per QALY.

CONCLUSIONS

There is insufficient evidence about the cost-effectiveness of SH for grade II haemorrhoids to recommend its routine use in place of RBL. Further information is needed from larger trials with a longer-term follow-up to inform subsequent economic evaluation.

Nicorandil associated anal ulceration

OBJECTIVE

Nicorandil is a vasodilator used to control angina. It has been associated with oral and anal ulceration that resolves upon withdrawal of the drug.

PATIENTS AND METHODS

We report a series of 13 patients with nonspecific anal ulceration all of whom were receiving nicorandil for control of symptoms of ischaemic heart disease.

RESULTS

All the ulcers had similar clinical and histological appearances. All the ulcers healed on withdrawal of the drug.

CONCLUSION

Nicorandil-associated anal ulceration should be considered in the differential diagnoses of nonhealing anal ulcers.

Arterial wall renin

Aortic homogenates contain proteolytic enzymes which will release angiotensin I (AI) from renin substrate. Some of these are active at low pH and are probably unrelated to renin. Renin-like activity in the rat measured at the optimum pH of 6.5 is altered in parallel with plasma renin in a wide variety of situations. The two diverge only in non-steady state situations. Studies have therefore been carried out after bilateral nephrectomy and after the injection of renal renin into nephrectomized rats. In each case aortic renin-like activity was cleared much more slowly than plasma renin, and the blood pressure change was related to aortic renin-like activity rather than to plasma renin. The blood pressure response to the converting enzyme inhibitor teprotide was also related to the former rather than the latter. Immunofluorescent studies of the aorta and the intrasplenic arteries from rats injected with mouse renin showed that renin was taken up predominantly into the media and persisted at this site. Thus, the uptake of renal renin from plasma by both large and small arteries is probably an important step in the physiology of the renin-angiotensin system and mediates renin-induced changes in peripheral resistance and blood pressure. However, we have no evidence for the hypothesis that selective accumulation of renin in the resistance vessel walls causes hypertension when circulating levels of renin are normal.

Arterial wall uptake of renal renin and blood pressure control

We have studied the contribution of circulating renin of renal origin to renin-like activity within the arterial wall and to blood pressure. Bolus injections of renin sufficient to elevate blood pressure by 44.7 mm Hg caused aortic renin to rise from 0.13 to 1.48 ng angiotensin I/100 mg/hr in nephrectomized rats. Elevation of aortic renin was still present at 6 hours, and this was associated with significant blood pressure elevation (p less than 0.05) which could be reversed by infusion of sarcosine, alanine, angiotensin II (saralasin). Prevention of the pressor effect by pretreatment with the converting enzyme inhibitor captopril did not reduce renin uptake. When kidneys were left in situ, although significant uptake of renin could be demonstrated 1 hour after injection, the increase at 3 hours was no longer significant (p greater than 0.05) and blood pressure returned to normal by 1 1/2 hours. This change in blood pressure may be related to the much more rapid clearance of circulating renin in the presence of normal kidneys or to other renal factors influencing the blood pressure response. The present studies demonstrate therefore that most of the renin-like activity within the aortic wall is derived from plasma renin and it seems probable that this component of the renin-angiotensin system plays an important role in blood pressure maintenance in the nephrectomized rats injected with renin. The relationship is less obvious in the presence of normal kidneys where additional influences may come into play.

Renin in the arterial wall

Homogenates of rat aortic wall can generate angiotensin I when incubated with nephrectomised rat plasma. This renin-like activity is due to a mixture of proteolytic enzymes. Thus the capacity to generate angiotensin I is greater at pH 5.3 than pH 6.5, although the latter is the pH optimum for rat renal renin. The present work addresses itself to two questions. Is this activity derived from plasma renin? Secondly, does vascular renin-like activity play a role in blood pressure control? Plasma and aortic renin were altered by bilateral nephrectomy and modulation of salt intake. In addition four models of hypertension were studied (early and chronic Goldblatt 2-kidney 1-clip, DOC-salt and spontaneous hypertension). The results indicated that in steady state conditions, aortic and plasma renin-like activity (measured with an incubation pH of 6.5) changed in parallel. When plasma renin was altered acutely however by intravenous injection of renin into nephrectomised rats the half-life of plasma renin was much shorter than the half life of aortic renin. Under these circumstances the pressor response to renin correlated much better with aortic than with plasma renin-like activity. Whilst these studies suggest therefore that renin taken up by the arterial wall is an important determinant of blood pressure, they provide no evidence that accumulation of renin locally produces hypertension in the presence of normal or low plasma renin activity.

Vascular renin as a determinant of the circulatory response to renin

The effect of an injection of partially purified rat renin on the blood pressure, plasma and aortic renin was studied in rats 18 hours after bilateral nephrectomy. Blood pressure rose and remained elevated 6 hours after renin injection, returning to normal at 9 hours. Aortic renin concentration was increased and showed a similar response pattern to blood pressure whereas plasma renin concentration fell to subnormal levels within 3 hours. The blood pressure response was prevented by converting enzyme inhibition and at 3 and 6 hours was reversed by saralasin infusion. These results demonstrate that circulating renin is taken up by vascular tissue and the pressor response to exogenous renin is related to aortic but not plasma renin.

Skin collagen biosynthesis in patients with rheumatoid arthritis treated with D-penicillamine

Collagen biosynthesis was measured in skin biopsies taken from 13 patients with rheumatoid arthritis before and after at least 6 months' continuous treatment with D-penicillamine, 1.0 g/day. There was a significant 36% reduction in mean collagen biosynthesis (p less than 0.0125) as assayed by 14C-hydroxyproline formation from 14C-proline during 24 h of tissue culture. The changes in 14C-hydroxyproline formation were correlated with the total doses of D-penicillamine taken (r = 0.71, p less than 0.01) and the falls in ESR (r = 0.72, p less than 0.01). No significant change in general protein syntehsis was observed. 500 microgram/mlD-penicillamine added to skil cultures in vitro inhibited both collagen and general protein synthesis (p less than 0.01). It is suggested that the clinical improvement induced by D-penicillamine could reflect an inhibition of collagen proliferation in the synovium.