Randomised, double-blind, placebo-controlled clinical trial investigating the effects of inorganic nitrate in hypertension-induced target organ damage: protocol of the NITRATE-TOD study in the UK

INTRODUCTION

Arterial stiffness and left ventricular (LV) hypertrophy are the key markers of hypertensive target organ damage (TOD) associated with increased cardiovascular morbidity and mortality. We have previously shown that dietary inorganic nitrate supplementation lowers blood pressure (BP) in hypertension, however, whether this approach might also improve markers of hypertensive TOD is unknown. In this study, we will investigate whether daily dietary inorganic nitrate administration reduces LV mass and improves measures of arterial stiffness.

METHODS AND DESIGN

NITRATE-TOD is a double-blind, randomised, single-centre, placebo-controlled phase II trial aiming to enrol 160 patients with suboptimal BP control on one or more antihypertensives. Patients will be randomised to receive 4 months once daily dose of either nitrate-rich beetroot juice or nitrate-deplete beetroot juice (placebo). The primary outcomes are reduction in LV mass and reduction in pulse wave velocity (PWV) and central BP.The study has a power of 95% for detecting a 9 g LV mass change by cardiovascular MRI (~6% change for a mildly hypertrophied heart of 150 g). For PWV, we have a power of >95% for detecting a 0.6 m/s absolute change. For central systolic BP, we have a>90% power to detect a 5.8 mm Hg difference in central systolic BP.Secondary end points include change in ultrasound flow-mediated dilation, change in plasma nitrate and nitrite concentration and change in BP.

ETHICS AND DISSEMINATION

The study was approved by the London-City and East Research Ethics Committee (10/H0703/98). Trial results will be published according to the Consolidated Standards of Reporting Trials statement and will be presented at conferences and reported in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03088514.

P2764Medical management of Staphylococcus aureus infective endocarditis: unexpectedly favourable outcomes in an aggressive disease

Introduction

Early surgical intervention (ESI) for infective endocarditis (IE) is associated with improved outcomes. Staphylococcus aureus endocarditis (SAE) is associated with particularly high rates of tissue destruction, morbidity and mortality. However, the question as to whether ESI is mandated in all SAE continues to be debated, in both native (NVE) and prosthetic (PVE) endocarditis.

Methods

Retrospective review of all IE cases presenting to our institution from October 2015 to January 2019. IE was diagnosed following imaging and microbiological protocols as per ESC guidance, and data were extracted for those with SAE. Patients with isolated cardiac implantable electronic device IE or bacteraemia secondary to indwelling long-term venous catheter infection were excluded (non-valvular IE).

Results

Valvular IE was diagnosed in 411 patients overall; NVE in 286 (69.6%) and PVE in 125 (30.4%). S aureus was isolated in 111 patients (28.1%), of whom 5 had a Methicillin-resistant strain. SAE was confirmed in a similar proportion of NVE and PVE cases [83/111 (74.8%) and 28/111 (25.2%), respectively]. Surgical intervention was mandated in 35/83 with NVE (42.2%) and 11/28 (39.3%) with PVE, lower than in our overall cohort (55.9% and 48.8%, respectively).

In-hospital SAE mortality was 16.2% overall (18.4% medical vs 13.0% surgical), and contributes a significant proportion to overall mortality (29% to medical & 26% to surgical mortality). Figure 1 identifies the cause of death per mode of treatment, highlighting the aggressive nature of S aureus infection (abscess, disseminated infection and septic shock; n=8), the importance of advanced non-cardiac comorbidity precluding intervention (n=3) and ongoing intravenous drug use in those with PVE (n=4). However, medical management was successful in 57.8% (38/83) of NVE and 60.7% (17/28) of PVE cases, both in hospital and to a minimum follow-up of 3-months.

Conclusion

Staphylococcus aureus is virulent and highly pathogenic, driving severe sepsis and advanced tissue destruction in SAE. Despite this, medical management can be successful when following international guidance, but requires co-ordinated care driven by a multidisciplinary IE team at a cardiothoracic centre.

Quantifying distraction and interruption in urological surgery

BACKGROUND

To enhance safety in surgery, it is necessary to develop a variety of tools for measuring and evaluating the system of work. One important consideration for safety in any high-risk work is the frequency and effect of distraction and interruption.

AIM

To quantify distraction and interruption to the sterile surgical team in urology.

METHODS

Observation of the behaviour of the surgical team and their task activity determined distraction and interruption recorded. Using an ordinal scale, an observer rated each salient distraction or interruption observed in relation to the team's involvement.

RESULTS

The frequency of events and their attached ratings were high, deriving from varying degrees of equipment, procedure and environment problems, telephones, bleepers and conversations.

DISCUSSION

With further refinement and testing, this method may be useful for distinguishing ordinal levels of work interference in surgery and helpful in raising awareness of its origin for postoperative surgical team debriefing.