Development of delivery indicators and delivery enablers for cardiovascular disease in the UK: a modified Delphi study

INTRODUCTION

Standards to define and measure quality in healthcare for cardiovascular disease risk reduction and secondary prevention are available, but there is a paucity of indicators that could serve as facilitators of structural change at a system level. This research study aimed to develop a range of delivery indicators to help cardiac clinical networks assess delivery of and progress towards cardiovascular disease objectives.

METHODS

This study used an adapted version of the European Society of Cardiology's four-step process for the development of quality indicators. The four steps in this study were as follows: identify critical factors of enablement, construct a list of candidate indicators, select a final set of indicators and assess availability of national data for each indicator. In this iterative process, a core project group of six members was supported by a wider review group of 21 people from the National Health Service (NHS) clinical and management personnel database.

RESULTS

The core project group identified six relevant cardiovascular disease priorities in the NHS Long Term Plan and used an iterative process to identify 21 critical factors that impact on their implementation. A total of 57 potential indicators that could be measures of implementation were developed. The core project group agreed on a set of 38 candidate indicators that were circulated to the review group for rating. Based on these scores, the core project group excluded 5 indicators to arrive at a final set of 33 delivery indicators. National datasets were available for 22 of the final indicators, which were designated as delivery indicators. The remaining 11, for which national datasets were not available but locally available datasets could be used, were designated as delivery enablers.

CONCLUSION

The suite of delivery indicators and delivery enablers for cardiovascular disease could allow a more focused evaluation of factors that impact on delivery of healthcare for cardiovascular disease.

Uncovering the treatable burden of severe aortic stenosis in the UK

OBJECTIVE

To estimate the population prevalence and treatable burden of severe aortic stenosis (AS) in the UK.

METHODS

We adapted a contemporary model of the population profile of symptomatic and asymptomatic severe AS in Europe and North America to estimate the number of people aged ≥55 years in the UK who might benefit from surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI).

RESULTS

With a point prevalence of 1.48%, we estimate that 291 448 men and women aged ≥55 years in the UK had severe AS in 2019. Of these, 68.3% (199 059, 95% CI 1 77 201 to 221 355 people) would have been symptomatic and, therefore, more readily treated according to their surgical risk profile; the remaining 31.7% of cases (92 389, 95% CI 70 093 to 144 247) being asymptomatic. Based on historical patterns of intervention, 58.4% (116 251, 95% CI 106 895 to 1 25 606) of the 199 059 symptomatic cases would qualify for SAVR, with 7208 (95% CI 7091 to 7234) being assessed as being in a high, preoperative surgical risk category. Among the remaining 41.6% (82 809, 95% CI 73 453 to 92 164) of cases potentially unsuitable for SAVR, an estimated 61.7% (51 093, 95% CI 34 780 to 67 655) might be suitable for TAVI. We estimate that 172 859 out of 291 448 prevalent cases of severe AS (59.3%) will subsequently die within 5 years without proactive management.

CONCLUSIONS

These data suggest a high burden of severe AS in the UK requiring surgical or transcatheter intervention that challenges the ongoing capacity of the National Health Service to meet the needs of those affected.

Impact of call-to-balloon time on 30-day mortality in contemporary practice

OBJECTIVE

Studies reporting an association between treatment delay and outcome for patients with ST segment elevation myocardial infarction (STEMI) have generally not included patients treated by a primary percutaneous coronary intervention (PPCI) service that systematically delivers reperfusion therapy to all eligible patients. We set out to determine the association of call-to-balloon (CTB) time with 30-day mortality after PPCI in a contemporary series of patients treated within a national reperfusion service.

METHODS

We analysed data on 16 907 consecutive patients with STEMI treated by PPCI in England and Wales in 2011 with CTB time of ≤6 hours.

RESULTS

The median CTB and door-to-balloon times were 111 and 41 min, respectively, with 80.9% of patients treated within 150 min of the call for help. An out-of-hours call time (58.2% of patients) was associated with a 10 min increase in CTB time, whereas inter-hospital transfer for PPCI (18.5% of patients) was associated with a 49 min increase in CTB time. CTB time was independently associated with 30-day mortality (p<0.0001) with a HR of 1.95 (95% CI 1.54 to 2.47) for a CTB time of >180-240 min compared with ≤90 min. The relationship between CTB time and 30-day mortality was influenced by patient risk profile with a greater absolute impact of increasing CTB time on mortality in high-risk patients.

CONCLUSION

CTB time is a useful metric to assess the overall performance of a PPCI service. Delays to reperfusion remain important even in the era of organised national PPCI services with rapid treatment times and efforts should continue to minimise treatment delays.

Coronary artery disease in the military patient

Ischaemic heart disease is the most common cause of sudden death in the UK, and the most common cardiac cause of medical discharge from the Armed Forces. This paper reviews current evidence pertaining to the diagnosis and management of coronary artery disease from a military perspective, encompassing stable angina and acute coronary syndromes. Emphasis is placed on the limitations inherent in the management of acute coronary syndromes in the deployed environment. Occupational issues affecting patients with coronary artery disease are reviewed. Consideration is also given to the potential for coronary artery disease screening in the military, and the management of modifiable cardiovascular disease risk factors, to help decrease the prevalence of coronary artery disease in the military population.

The national infarct angioplasty project: UK experience and subsequent developments

The UK had previously established a comprehensive strategy for in-hospital nurse-led thrombolysis for patients with ST-elevation myocardial infarction, with a growing use of pre-hospital thrombolysis by paramedical staff in the ambulance services. The National Infarct Angioplasty Project was sponsored by the government and examined the introduction of primary percutaneous coronary angioplasty (PPCI) in a variety of urban, rural and mixed communities. The project found that PPCI could be delivered within acceptable timelines, would be cost-effective, and could be delivered to the majority of the population. A project was therefore undertaken in England to transform services. There has been a rapid change and by 2012/13 over 95% of eligible patients received PPCI. Survival of patients with STEMI has improved over time and length of stay in hospital halved. However, nearly a quarter of STEMI patients do not receive reperfusion therapy (often because of late presentation) and additional work is needed to minimise delays to treatment. There are unexplained differences between regions in numbers of PPCI procedures per million population, and there is also variance between centres in the proportion of patients who are in shock or on a ventilator. Additional research is needed to ensure a consistent approach for these sick patients, who might have the most to gain from early treatment. The national audit programmes have been instrumental in measuring the changes in strategies, monitoring performance and highlighting the associated improvements in outcomes. A new risk model is being developed to allow a more comprehensive comparison of outcomes in different hospitals.

The importance of audit to monitor applications of procedures and improve primary angioplasty results

Although clinical trials have demonstrated that primary percutaneous coronary intervention (PPCI) provides better outcomes than thrombolysis for STEMI, it cannot be assumed that similar results can be obtained in day-to-day practice. To determine whether standards are being met, continuous audit of PPCI programmes is necessary, with appropriate feedback to participating centres and operators. Both the MINAP and BCIS national audit projects allow central electronic collection of data on consecutive patients presenting to every hospital involved in the acute management of these patients. Regular programmed feedback is provided to centres performing primary PCI that attempts to take account of statistical variation and differences in case mix between units by making use of funnel plots, statistical process control graphs and risk adjustment models. This reporting of "process" and "outcome" data, both confidentially and within the public domain, has been used to drive up clinical performance and has been associated with steady improvements and reduced inequalities of care.

Public access defibrillation remains out of reach for most victims of out-of-hospital sudden cardiac arrest

INTRODUCTION

Public access defibrillation (PAD) prior to ambulance arrival is a key determinant of survival from out-of-hospital (OOH) cardiac arrest. Implementation of PAD has been underway in the UK for the past 12 years, and its importance in strengthening the chain of survival has been recognised in the government's recent 'Cardiovascular Disease Outcomes Strategy'. The extent of use of PAD in OOH cardiac arrests in the UK is unknown. We surveyed all OOH cardiac arrests in Hampshire over a 12-month period to ascertain the availability and effective use of PAD.

METHODS

A retrospective review of all patients with OOH cardiac arrest attended by South Central Ambulance Service (SCAS) in Hampshire during a 1-year period (1 September 2011 to 31 August 2012) was undertaken. Emergency calls were reviewed to establish the known presence of a PAD. Additionally, a review of all known PAD locations in Hampshire was undertaken, together with a survey of public areas where a PAD may be expected to be located.

RESULTS

The current population of Hampshire is estimated to be 1.76 million. During the study period, 673 known PADs were located in 278 Hampshire locations. Of all calls confirmed as cardiac arrest (n=1035), the caller reported access to an automated external defibrillator (AED) on 44 occasions (4.25%), successfully retrieving and using the AED before arrival of the ambulance on only 18 occasions (1.74%).

CONCLUSIONS

Despite several campaigns to raise public awareness and make PADs more available, many public areas have no recorded AED available, and in those where an AED was available it was only used in a minority of cases by members of the public before arrival of the ambulance. Overall, a PAD was only deployed successfully in 1.74% OOH cardiac arrests. This weak link in the chain of survival contributes to the poor survival rate from OOH cardiac arrest and needs strengthening.

Percutaneous coronary intervention: recommendations for good practice and training

Cardiologists undertaking percutaneous coronary intervention (PCI) are excited by the combination of patient and physician satisfaction and technological advance occurring on the background of the necessary manual dexterity. Progress and applicability of percutaneous techniques since their inception in 1977 have been remarkable; a sound evidence base coupled with the enthusiasm and ingenuity of the medical device industry has resulted in a sea change in the treatment of coronary heart disease (CHD), which continues to evolve at breakneck speed. This is the third set of guidelines produced by the British Cardiovascular Intervention Society and the British Cardiac Society. Following the last set of guidelines published in 2000, we have seen PCI activity in the UK increase from 33,652 to 62,780 (87% in four years) such that the PCI to coronary artery bypass grafting ratio has increased to 2.5:1. The impact of drug eluting stents has been profound, and the Department of Health is investigating the feasibility of primary PCI for acute myocardial infarction. Nevertheless, the changes in the structure of National Health Service funding are likely to focus our attention on cost effective treatments and will require physician engagement and sensitive handling if we are to continue the rapid and appropriate growth in our chosen field. It is important with this burgeoning development now occurring on a broad front (in both regional centres and district general hospitals) that we maintain our vigilance on audit and outcome measures so that standards are maintained for both operators and institutions alike. This set of guidelines includes new sections on training, informed consent, and a core evidence base, which we hope you will find useful and informative.

Clopidogrel for prevention of major cardiac events after coronary stent implantation: 30-day and 6-month results in patients with smaller stents

OBJECTIVES

We developed this study to assess the procedural outcome, complications, and clinical follow-up in patients treated with different antiplatelet regimens after intracoronary stent implantation with small stents. Three hundred sixty-one consecutive patients, in whom at least one 3.0-mm intracoronary stent was implanted, were studied.

METHODS

The study was a prospective, observational registry of unselected consecutive patients treated in our institution. Patients who underwent stent implantation between December 1997 and July 1998 were treated with aspirin and ticlopidine; those who received stents between August 1998 and February 1999 were treated with aspirin and clopidogrel.

RESULTS

In the group treated with ticlopidine, there were 190 patients who had 253 lesions treated with 274 stents. Mean age was 59.1 years, 72% were male, 31% had unstable angina, 64% had 1 stent, 36% had >1 stent, and 23% had multivessel intervention. In the group treated with clopidogrel, there were 171 patients who had 226 lesions treated with 245 stents. Mean age was 60.4 years, 79% were male, 26% had unstable angina, 70% had 1 stent, 30% had >1 stent, and 26% had multivessel intervention. Complications at 30 days in the ticlopidine group were death in 1 (0.5%), stent occlusion in 3 (1. 6%; all reopened with repeat angioplasty), non-Q-wave myocardial infarction in 2 (1%), and urgent revascularization in 4 (2%). Complications at 30 days in the clopidogrel group were noncardiac death in 1 (1.2%), cardiac death in 1 (1.2%), stent occlusion in 0, non-Q-wave myocardial infarction in 3 (1.8%), and urgent revascularization in 0. Follow-up was available in 100% of patients in both groups (mean 253 +/- 75 days in the ticlopidine group, 198 +/- 53 days in the clopidogrel group). Complications at >30 days in the ticlopidine group were death in 1 and clinical restenosis in 11 (5.8%); 1 additional patient had an admission with unstable angina to the local hospital. Hence, recurrent angina as a consequence of target lesion restenosis occurred in 5.8%. Complications at >30 days in the clopidogrel group were death in 0 and clinical restenosis in 8 (4.7%); 2 additional patients were admitted with unstable angina to the local hospital, and 1 patient had a myocardial infarction 164 days after stent implantation. Hence, recurrent angina as a consequence of target lesion restenosis occurred in 4.7%. There were no significant differences in complications between the 2 groups.

CONCLUSIONS

Our observations suggest that clopidogrel can be used instead of ticlopidine in patients treated with stents with a diameter of </=3.0 mm, without any increase in major adverse cardiac events, both within the first 30 days and at medium-term follow-up. Clopidogrel has significant cost advantages over ticlopidine, and carries a superior side-effect profile. We suggest that, in combination with aspirin, clopidogrel should replace ticlopidine as standard antiplatelet therapy after intracoronary stent implantation.

Intracoronary Multi-link stents: experience in 218 patients using aspirin alone

OBJECTIVES

To assess procedural outcome, complications, and clinical follow up in 218 patients who underwent treatment with 297 Multi-link (Guidant) stents implanted without the use of intravascular ultrasound (IVUS) or quantitative coronary angiography (QCA), and using aspirin alone as antiplatelet therapy.

METHODS

The case records and angiograms were reviewed and the patients were contacted by telephone to determine their symptoms and any adverse events at follow up. Data were analysed using Fisher's exact test.

RESULTS

Of the 218 patients included in the study, 45 had multivessel intracoronary intervention, and 55 had unstable angina. The mean (SD) length of hospital stay following the procedure was 2.0 (2.1) days. There were two early deaths at less than 30 days, and two deaths during follow up at more than 100 days. Ten patients suffered complications during the first 30 days: four had subacute stent thrombosis, of whom two died and two were treated successfully with coronary artery bypass grafting; five had a non-Q wave myocardial infarction; and one had a femoral false aneurysm. Patient outcome was analysed according to stent diameter (3.0 mm or less, or 3.5 mm or more) and by angina status (stable or unstable). In patients in whom at least one stent was 3.0 mm diameter, four of 86 patients suffered acute stent occlusion, whereas in the 132 patients in whom all stents were at least 3.5 mm diameter there were no cases of stent occlusion (p = 0.02). In the unstable angina group two of 55 patients suffered acute stent occlusion compared to two of 163 patients in the stable angina group (NS). In patients with unstable angina and at least one stent of 3.0 mm diameter, the acute occlusion rate was 7.1% (two of 28 patients). Three of the four patients with stent occlusion had undergone complex procedures. Twenty eight patients were restudied for recurrent symptoms during the follow up period. Of these, eight patients had restenosis within their stent. In seven of these patients the stent size was 3.0 mm diameter, and in the remaining patient the stent size was 4.0 mm diameter. Three of the 28 patients restudied had developed new disease remote from the stented site, and 17 had patent stents and no significant other coronary lesion.

CONCLUSIONS

This study suggests that coronary intervention using the Multi-link stent is safe and effective using aspirin alone, without IVUS or QCA, when stent diameter is greater than 3.0 mm. All cases of stent occlusion in this series occurred in patients in whom at least one stent was 3.0 mm diameter, with stent occlusion being higher in patients with unstable angina compared to those with stable angina. Additional antiplatelet therapy may be beneficial in those patients in whom Multi-link stent diameter is less than 3.5 mm, particularly in those with unstable angina, but is not necessary for patients receiving Multi-link stents of 3.5 mm diameter or greater.

Planning for coronary angioplasty: guidelines for training and continuing competence. British Cardiac Society (BCS) and British Cardiovascular Intervention Society (BCIS) working group on interventional cardiology

The following recommendations are made: 1 Existing centres undertaking angioplasty should increase their activity, and the target figure of 400 PTCA procedures per million of the United Kingdom population should be achieved by the end of 1996-97, or immediately thereafter. 2 Angioplasty centres should be appropriately equipped to undertake PTCA safely and effectively and provide a reliable emergency service. They should have a minimum of two trained PTCA operators jointly undertaking a minimum of 200 procedures per year at that centre, and have regular meetings to share experience. 3 Angioplasty operators should ensure that where the need arises patients undergoing PTCA can receive immediate attention from a trained operator at any time until discharge from hospital. 4 Trained operators should undertake at least 1-2 PTCA procedures per week (> 60 procedures per year) to maintain competence, and those undertaking so few procedures should increase their activity over the next three years to more than 100 a year. 5 Trainers should have performed at least 500 procedures before formally training others and should undertake a minimum of 125 procedures a year to maintain accreditation as a trainer. 6 Surgical cover for PTCA procedures should be mandatory and on site cover remains the strongly preferred option. Where surgical cover is provided off site, this should be at a centre less than 30 minutes away by road. Whether provided on or off-site it should be possible to establish cardiopulmonary bypass within 90 minutes of the decision being made to refer the patient for surgery. 7 All operators and interventional centres should audit their activity and results, review these data locally with colleagues, and provide regular audit returns to the national database run by BCIS. This will allow future recommendations concerning standards to take more account of risk stratification and actual outcomes, and not place such emphasis merely on volumes of activity. 8 These recommendations should be reviewed in three years.

Late functional results after surgical closure of acquired ventricular septal defect

To assess the longer term outlook for patients who have undergone surgery for acquired (postinfarction) ventricular septal defect, we interviewed and studied 60 survivors from a single regional cardiac center between 3 and 144 months after the operation. Including the patients who died within 1 month of the operation, the 5-, 10-, and 14-year survivals (with standard errors) were 69% (65% to 74%), 50% (44% to 57%), and 37% (27% to 46%). Eighty-two percent of patients were in New York Heart Association class I or II. Ten patients (17%) had a persisting but not hemodynamically significant ventricular septal defect. Mean left ventricular ejection fraction was reduced at 0.39 (standard deviation 0.15), but this did not correlate with either New York Heart Association class or exercise tolerance. Twenty-eight patients (47%) had asymptomatic arrhythmias (17 with ventricular premature beats). Angina and other medical problems were not prevalent.

Magnetic resonance angiography in subclavian steal syndrome

A case is reported of a patient with the subclavian steal syndrome in whom the reversed blood flow of the vertebral artery was shown by phase encoded magnetic resonance angiography.

Left ventricular energetics: heat production by the human heart

OBJECTIVE

The aim was to examine the effect of coronary artery disease on human left ventricular energetics by a comparison of left ventricular oxygen consumption and heat production. The usefulness of measurement of left ventricular heat production for the detection of the expected change in left ventricular energetics produced by atrial pacing to a faster heart rate was also assessed.

METHODS

Forty six patients (mean age 57 years; 31 men) undergoing cardiac catheterisation and coronary arteriography for the investigation of chest pain were studied. Normal left ventricular function and normal coronary arteries were present in eight and 38 had atheromatous coronary artery disease. Left ventricular heat production was calculated from coronary blood flow, the coronary arteriovenous (aorta-coronary sinus) temperature difference, and the areas under thermodilution curves recorded in the aorta and coronary sinus after injection of cold saline into the pulmonary artery. Mean external left ventricular power was calculated from mean arterial blood pressure and cardiac output. Left ventricular mechanical efficiency was derived from heat production and the energy value of myocardial oxygen use, assuming aerobic metabolism. In 27 patients studies were repeated during atrial pacing from the coronary sinus.

RESULTS

At rest under basal conditions left ventricular heat production was 2.4(SD 1.0) W in patients with normal hearts and 3.1(1.4) W in patients with coronary disease (NS). Mechanical efficiency was 44.2(9.7)% in the normal patients and 30.7(10.9)% in those with coronary disease (p = 0.003). During atrial pacing to a faster heart rate left ventricular energy supply increased from 4.6(2.7) W to 5.9(3.3) W (p < 0.0005), and heat production increased from 3.0(1.6) W to 4.6(2.4) W (p < 0.0005), but mean external power was not altered. As the extra energy used during pacing was "wasted" as heat, there was a significant fall in left ventricular mechanical efficiency with pacing from 33.9(13.5)% to 18.9(15.2)% (p < 0.0005).

CONCLUSIONS

These results show the effect of coronary artery disease on the energetics of left ventricular function. They also show that the method and equipment can detect the expected alteration in left ventricular energetics produced by atrial pacing. The measurement of left ventricular heat production and oxygen consumption allows assessment of the total left ventricular energy flux, and may be useful for the evaluation of drug treatment with such as inotropes and vasodilators, and for the investigation of the functional consequences of left ventricular disease.

Adenosine infusion for the reversal of pulmonary vasoconstriction in biventricular failure. A good test but a poor therapy

BACKGROUND

Elevation of pulmonary vascular resistance is an important determinant of right ventricular function in patients with end-stage biventricular heart failure. Vasodilator drug therapy directed at the pulmonary vasculature is used in the hemodynamic assessment of patients for orthotopic heart transplantation, and therapy aimed at decreasing pulmonary vascular resistance and transpulmonary pressure gradient has been advocated in patients awaiting heart transplantation. Adenosine infusion has been shown to cause selective pulmonary vasodilatation in normal subjects and in patients with primary pulmonary hypertension but has not been assessed in patients with biventricular heart failure.

METHODS AND RESULTS

Using two infusion doses, we studied the pulmonary and renal hemodynamic effects of adenosine on patients referred for heart transplantation (n = 21) and compared it with sodium nitroprusside (n = 18). Patients received 30% oxygen via face mask throughout the study. Adenosine at 100 micrograms/kg min achieved the same percentage fall in pulmonary vascular resistance as nitroprusside (41 +/- 6% versus 42 +/- 4%) and a greater and more consistent fall in transpulmonary pressure gradient (35 +/- 6% versus 9 +/- 30%, p less than 0.02). The mean arterial blood pressure fell by 16 mm Hg with nitroprusside but was unchanged by adenosine, indicating that in contrast to nitroprusside, adenosine acted as a selective pulmonary vasodilator. Despite this, cardiac index showed only a modest increase with adenosine (1.73 +/- 0.09 to 1.89 +/- 0.16 l.m-2, p less than 0.05), and there was a rise in pulmonary capillary wedge pressure from baseline at the higher dose (29.7 +/- 2.5 to 33.4 +/- 3.4 mm Hg, p less than 0.05). Renal blood flow was unchanged during adenosine infusion.

CONCLUSIONS

Adenosine is a potent selective pulmonary vasodilator in patients with biventricular heart failure and is preferable to sodium nitroprusside as a test for the reversibility of pulmonary vasoconstriction. However, its deleterious effects on left atrial pressure make it unsuitable as a therapeutic agent in patients awaiting heart transplantation.

Late rupture of a superior intercostal artery following repair of aortic coarctation

Having had surgical repair of aortic coarctation at the age of 12 years, and re-operation at the age of 19 years for stenosis at the site of the previous repair, a 29 years old man presented as an emergency with a 24 hour history of interscapular pain, haemoptysis and collapse. At thoracotomy he was found to have a ruptured superior intercostal artery which was ligated. Spontaneous rupture of an intercostal artery has not been previously recorded.

Use of computed tomographic scanning and aortography in the diagnosis of acute dissection of the thoracic aorta

Before the introduction of computed tomographic (CT) scanning, aortography was the investigation of choice for acute aortic dissection. Between 1978 and 1982, 24 patients were referred to the Brompton Hospital with suspected acute thoracic aortic dissection; all had aortography with diagnosis confirmed at surgery (n = 12) or necropsy (n = 2) or supported by clinical outcome (n = 8). One patient in whom aortography was negative had type B dissection at necropsy and another patient was lost to follow up. CT scanning became available in this unit in 1983 and between 1983 and 1987 was used as the only imaging investigation in 32 patients with suspected acute dissection of the thoracic aorta while in a further 22 patients aortography was used alone. Results were confirmed at surgery (n = 18), necropsy (n = 3), or supported by clinical outcome (n = 31). Two patients were lost to follow up. In an additional 16 patients both aortography and CT scanning were performed with concordant findings in 10. In six in whom the results were discordant, aortography was normal in three in whom subsequent CT scanning showed type B dissection and CT scanning was normal in three patients in whom aortography showed type A dissection. Both CT scanning and aortography are reliable techniques for assessment of suspected acute dissection of the thoracic aorta. Both techniques misdiagnose occasionally and the frequency of misdiagnosis will be minimised by performing both investigations in patients where the level of clinical suspicion is high and the initial investigation negative. CT scanning tends to miss type A dissection and in view of the success of surgery in this condition this failing has the more serious clinical consequences.

Clinical correlates of angiographically diagnosed idiopathic pulmonary hypertension

During 1970-87 43 patients with unexplained pulmonary hypertension (mean pulmonary arterial pressure greater than 25 mm Hg) were admitted to the Brompton Hospital and classified by angiographic criteria as having either symmetrical peripheral pulmonary artery pruning (thought to represent primary plexogenic pulmonary arteriopathy), n = 21, or asymmetrical pulmonary arterial occlusions (thought to represent chronic thromboembolic disease), n = 22. Patients with symmetrical pulmonary arteriopathy had significantly higher mean pulmonary arterial pressures (67 mm Hg) at the time of presentation than those with asymmetrical pulmonary arteriopathy (49 mm Hg). Clinical distinction between these two groups was impossible. Survival from the time of diagnosis was similarly poor in the two groups (26 weeks and 38 weeks) and did not correlate with any of the haemodynamic measurements. The difficulties in making distinctions between these conditions are discussed.

The clinical features, management and outcome of persistence of the arterial duct presenting in adult life

We have reviewed the 25 patients who, between 1973 and 1988, presented to the Brompton Hospital in adulthood with persistence of the arterial duct (ductus arteriosus). As pulmonary arteriolar resistance is the main determinant of management and prognosis in this condition, the patients were divided into groups with either normal or mild elevation of resistance (less than 10 units/m2: 19 patients) or with severe elevation (greater than 10 units/m2: 6 patients). Patients with normal pressures or mild elevation tended to be older (mean age 45 years). Many (70%) were asymptomatic, but dyspnoea with signs of left heart failure was the commonest presenting complaint. Surgical closure of the duct was performed in 16 with good result in all. Survival for the entire group, however, was long. There was a symptomatic indication for surgery (due to hyperdynamic circulation) in 5. In those with severely elevated pulmonary arteriolar resistance, the mean age of presentation was 31 years and the survival short. The commonest presenting symptom was dyspnoea. Surgical closure of the duct was attempted in two patients but with a poor outcome in both. All patients with an elevated resistance had developed this complication by the third decade of life. Significant elevation was not a feature of older patients, suggesting that, in this age group, the risk of elevation is slight. Surgery, nonetheless, may be indicated for relief of symptoms due to a large systemic to pulmonary shunt.

Heat production by the human left ventricle: measurement by a thermodilution technique

STUDY OBJECTIVE - The aim was to study the feasibility of measuring heat production by the human left ventricle with a view to using this variable as an index of left ventricular mechanical efficiency. DESIGN - The transcoronary temperature difference was derived from catheter mounted thermistors placed percutaneously in the aortic root and coronary sinus. Left ventricular blood flow was measured by continuous thermodilution in the coronary sinus, and heat removal by coronary venous blood was calculated from blood flow and the transcoronary temperature difference. Diffusional heat loss was measured using temperature/time curves recorded in aorta and coronary sinus after a bolus injection of cold saline into pulmonary artery. The heat loss from the system into the endothermic reactions of haemoglobin was calculated from left ventricular oxygen extraction using an assumed respiratory quotient. The energy released by left ventricular myocardial metabolism (EEO2, calculated from oxygen extraction), was compared to measured left ventricular heat production, and the mechanical efficiency of the left ventricle was calculated by the formula: Efficiency = (EEO2 - HLV)/EEO2. PATIENTS - Fifteen conscious patients with anginal chest pain were studied at the time of cardiac catherisation and coronary arteriography. MAIN RESULTS - The transcoronary temperature difference was in the range 0.10-0.32 (mean 0.21) degrees C. Total left ventricular heat production, equal to the sum of heat removed by the blood stream, diffusional loss and endothermic reactions (HLV) was in the range 1.5-4.6 (mean 2.7) watts. The values of EEO2 obtained were in the range 2.4-6.5 (mean 4.0) watts, and the calculated mechanical efficiency of the left ventricle was 0.24-0.55 (mean 0.34). CONCLUSIONS - The measurement of heat production by the human left ventricle is safe and practical. This technique promises to be of value in the clinical investigation of the relationship between myocardial function and energy utilisation.

Coronary arterial occlusion and myocardial infarction in acute myocarditis

Coronary arterial occlusion may occur experimentally during acute myocarditis but has not been documented in man. We report the case of a young female with severe myocarditis who later required cardiac transplantation and in whom coronary occlusion was demonstrated arteriographically before transplantation and by pathological examination of the heart after explantation.

Major complications of coronary arteriography: the place of cardiac surgery

The records of the catheter laboratory at St George's Hospital between 1983-1988 were reviewed to determine how often emergency coronary bypass surgery was performed because of a complication arising during elective coronary arteriography. A total of 11,216 cardiac procedures were performed; 5781 were confined to left ventricular angiography and coronary arteriography in patients with suspected coronary artery disease. Fourteen patients, whose investigation had been considered routine, suffered profound circulatory collapse during the procedure. Emergency cardiac surgery was undertaken in 13, with long term survival in 10. This experience suggests that, even in patients considered to be at low risk, there were major complications requiring emergency coronary surgery in at least 2.4 per 1000 coronary arteriograms performed. Survival after emergency cardiac surgery in these patients was 77%. These findings and the access to cardiac surgery should be considered when the development of facilities for cardiac catheterisation is planned.

Self injection with mercury

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Measurement of coronary sinus flow by thermodilution: observations on the effect of respiration and a review of the potential sources of error

In a series of experiments involving measurement of left ventricular blood flow by thermodilution in the coronary sinus, a consistent, but unexpected, variation in calculated coronary sinus flow, related to respiration, was seen. In some patients the variation was small, but in others it was as much as 300%. To discover its cause, five patients were investigated prospectively with continuous right atrial pressure monitoring during coronary flow measurement and respiratory manoeuvres. In three, ice-cold saline was injected into the right atrium during respiratory manoeuvres while coronary sinus temperature was monitored continuously and the position of the catheter was monitored fluoroscopically. The cause was found to be movement of the catheter such that thermistor approached the right atrium, and the variation was therefore spurious. We report these findings and discuss other known causes of inaccurate coronary flow measurement using the thermodilution technique.

The tricuspid valve: an unusual site of endocardial pacemaker lead fracture

Two patients are described in this article who developed fractures of transvenous endocardial pacing leads at the point of passage across the tricuspid valve. In one case life-threatening asystole occurred, emphasizing the potential seriousness of this complication.

Coronary arterial surgery in the elderly: its effect in the relief of angina

Financial and other constraints, such as operative risk, may prevent older patients being considered for coronary arterial bypass grafting. Grafting was performed in 315 elderly patients (244 males, 71 females, age 65-79, mean 69 years) between 1981-1986. All patients had limiting angina, 38% had rest pain, 90% were housebound and 80% had triple-vessel disease. Impairment of left ventricular function was absent in 46%, mild in 20%, moderate in 23% and severe in 10% of patients. Grafts (saphenous vein or internal mammary artery) were inserted into 3 vessels (52%), 4 vessels (42%), 5 vessels (6%), 6 vessels (0.5%). Death during surgery occurred in 1.6% and a further 3.5% of patients died later during the same admission (70% of deaths were among the 33% with preoperative moderate or severe left ventricular impairment). Surgical complications included myocardial infarction (8%), cerebrovascular accident (1%), transient cerebral vascular ischaemia (5%), chest infection (10%) and wound infection (4%). Median stay on the intensive care unit was 1 day and median total hospital stay 12 days. 299 patients therefore survived to leave hospital and follow-up data are available for 217 (72%) of these. 96% were subjectively improved by surgery, 88% being free of angina on no antianginal drugs a median of 72 weeks (range 8-307) and a further 8% not limited by angina on medical therapy a median of 85 weeks (range 9-302) after surgery. We conclude that coronary arterial surgery is an effective treatment for angina in the elderly. This will have consequences for future resource allocation if the elderly are not to be denied effective therapy because of financial rather than clinical restraints.

Left heart catheterization by direct ventricular puncture: withstanding the test of time

If retrograde arterial catheterization of the left ventricle fails because of a stenosed native or tissue valve or is contraindicated because of the presence of a mechanical aortic prosthesis, then alternative routes of access to the left ventricle are either transseptal or direct (transapical) left ventricular puncture. The transseptal approach is contraindicated in the presence of a mechanical mitral valve prosthesis. Under these circumstances we have used direct transapical left ventricular puncture in the treatment of 112 patients and have found this technique to be successful with little associated risk. A major complication occurred in 3% of the patients, but the study provided the required data in 95%, and these figures compare favorably with the reported results of transseptal catheterization.

Diagnostic features of localised pericardial constriction

We report a case of localised pericardial constriction leading to right ventricular outflow tract obstruction. Localised pericardial constriction is rare, but the diagnosis should be considered in patients who present with recurrent pericardial constriction following previous partial pericardiectomy. Close attention to physical findings may enable the diagnosis to be made prior to cardiac catheterisation.

Pulmonary embolectomy for acute massive pulmonary embolism: an analysis of 71 cases

Between 1964 and 1986 a total of 71 pulmonary embolectomies were performed for acute massive pulmonary embolism. All patients were severely compromised haemodynamically. Sixteen (64%) of 25 patients who had sustained significant periods of cardiac arrest before operation died. The principal cause of death in this group was severe neurological damage. Five (11%) of the 46 who had not had a cardiac arrest died. The 50 (70%) patients who survived did so largely without morbidity during their hospital admission and in the follow up period. Most were not treated with long term anticoagulants and only two had another embolism. When a patient with acute massive pulmonary embolism is too ill to be given thrombolytic treatment, or when thrombolysis is either contraindicated or too slow in producing benefit, pulmonary embolectomy remains an effective alternative treatment with an acceptable mortality.

Angina pectoris treated by ventricular plication

Objective analysis of the left ventricular angiogram in a patient with angina but normal coronary arteries showed an appreciable disturbance of regional wall movement. Because of persistent symptoms refractory to medical treatment left ventricular plication was undertaken. This resulted in a return to normal of a series of disturbances of left ventricular wall motion commonly found in patients with obstructive coronary disease, and a striking improvement in the patient's symptoms. The patient remains symptom free five years after operation.

Coronary artery aneurysms and myocardial infarction: adult sequelae of Kawasaki disease?

Coronary artery aneurysms developed in a 43 year old man who had suffered an acute myocardial infarction at the age of 30. In childhood he had had an illness that was consistent with Kawasaki disease, and it is suggested that the proximal discrete aneurysms and myocardial infarction may be the adult sequelae of this.

Characterisation of the normal right ventricular pressure-volume relation by biplane angiography and simultaneous micromanometer pressure measurements

The normal right ventricular pressure-volume relation was studied by recording biplane right ventriculograms with simultaneous high fidelity pressure recordings in 10 adults found to have normal coronary arteries and haemodynamic function at diagnostic cardiac catheterisation. Right ventricular volume was measured frame by frame from digitised ventriculograms by a modification of Simpson's rule. The accuracy of this method was tested in a study of 22 human and animal right ventricular casts. There was excellent agreement between calculated volumes and those measured by fluid displacement. The derived regression equations were used to correct right ventricular volumes calculated from in vivo studies. The mean (SD) end diastolic volume index for the group was 62 (13) ml/m2, the stroke volume index was 43 (8) ml/m2, and the ejection fraction was 62 (6)%. Right ventricular pressure-volume loops were generated by combining simultaneous volume and pressure curves. The normal right ventricular pressure-volume loop was triangular, departing significantly from the square or rectangle of the normal left ventricular pressure-volume loop. Ejection from the right ventricle began early during the pressure rise and continued as right ventricular pressure fell. As a result phases of isovolumic contraction and relaxation were difficult to define. These observations show that normal right ventricular pressure-volume relations differ considerably from those of the normal left ventricle, presumably reflecting the different loading conditions of the two ventricles.