How common is aortic dilatation?

Funding Acknowledgements

Type of funding sources: None.

Introduction

Aortic dilatation is most commonly associated with hypertension, bicuspid aortic valve and connective tissue diseases such as Marfan’s. It is a precursor to life threatening complications such as rupture or dissection of the aorta. The current ESC Guidelines recommend surgical intervention once the aortic diameter is >50 mm in patients with Marfan syndrome (Ic) and >55 mm in patients with a bicuspid or normal aortic valve morphology (IIb). There is currently a lack of literature on the prevalence of aortic dilatation in the general or even hospital population although there is historical data suggesting the incidence of thoracic aortic aneurysm to be 5.9 cases per 100,000.

Purpose

The aim is to investigate the prevalence of aortic dilatation by echocardiography in our hospital population which may help lay the foundation for population studies and identify prognostic factors which may determine the time of surgical intervention.

Methods

We carried out a retrospective survey using the digital echocardiogram archive and the electronic patient record system at our hospital. This survey covered the period between 1st October 2016 and 1st November 2018. For randomisation  purposes, all transthoracic echocardiograms (TTE) performed on every Thursday during this period were included. All patients with an echocardiographic report of aortic root or ascending aorta dilatation were enrolled. Other information including echocardiographic dimensions along with demographics and past medical history was collected.

Results

During this 24-month period, we analysed a total of 3019 TTEs. 209 patients (6.9%) were reported to have aortic dilatation. 137 (66%) were male and the median age was 67 years. The mean height and weight were 169cm and 80kg, respectively.  A bicuspid aortic valve was confirmed in 10 (4.8%) patients. 132 (63%) patients had a history of hypertension. On echocardiogram, 75 (36%) patients had septal hypertrophy and 26 (12.4%) had a dilated left ventricle.  

Conclusion

Our findings are unique and for the first time, to our knowledge, we report the echocardiographic prevalence of aortic dilatation in the hospital population (6.9%). It is a staggering 40-fold increase when compared to the the prevalence of aortic aneurysm, the most likely end point of aortic dilatation. Based on our figures, there would be at least 400 patients with a dilated aorta in a year in our hospital alone. The prevalence of bicuspid aortic valve in our cohort (4.8%) was nearly three times higher than the general population where it is quoted as 1-2%. Our study also emphasised the established link between hypertension and aortic dilatation with an increased frequency in our cohort (63%) compared to the global prevalence (31%). Given the devastating sequelae of aortic dilatation and its increased prevalence in our patient population, it will be very important to keep these patients under routine surveillance and particularly those with hypertension.

Rest versus exercise hemodynamics for middle cerebral artery aneurysms: a computational study

BACKGROUND AND PURPOSE

Exercise is an accepted method of improving cardiovascular health; however, the impact of increases in blood flow and heart rate on a cerebral aneurysms is unknown. This study was performed to simulate the changes in hemodynamic conditions within an intracranial aneurysm when a patient exercises.

MATERIALS AND METHODS

Rotational 3D digital subtraction angiograms were used to reconstruct patient-specific geometries of 3 aneurysms located at the bifurcation of the middle cerebral artery. CFD was used to solve for transient flow fields during simulated rest and exercise conditions. Inlet conditions were set by using published transcranial Doppler sonography data for the middle cerebral artery. Velocity fields were analyzed and postprocessed to provide physiologically relevant metrics.

RESULTS

Overall flow patterns were not significantly altered during exercise. Across subjects, during the exercise simulation, time-averaged WSS increased by a mean of 20% (range, 4%-34%), the RRT of a particle in the near-wall flow decreased by a mean of 28% (range, 13%-40%), and time-averaged pressure on the aneurysm wall did not change significantly. In 2 of the aneurysms, there was a 3-fold order-of-magnitude spatial difference in RRT between the aneurysm and surrounding vasculature.

CONCLUSIONS

WSS did not increase significantly during simulated moderate aerobic exercise. While the reduction in RRT during exercise was small in comparison with spatial differences, there may be potential benefits associated with decreased RRT (ie, improved replenishment of nutrients to cells within the aneurysmal tissue).

Sudden arrhythmic death syndrome: a national survey of sudden unexplained cardiac death

OBJECTIVE

To describe the characteristics of sudden arrhythmic death syndrome (SADS) and compare its incidence with official national mortality statistics for unascertained deaths.

DESIGN AND SETTING

Sudden unexplained deaths were prospectively surveyed through 117 coroners' jurisdictions in England. Consecutive cases meeting the following criteria were included: white Caucasian, aged 4-64 years, no history of cardiac disease, last seen alive within 12 h of death, normal coroner's autopsy, cardiac pathologist's confirmation of a normal heart and negative toxicology.

MAIN OUTCOME MEASURES

The estimated mortality from SADS was calculated and the official mortality statistics for unascertained causes of deaths in 4-64-year-olds was identified for the same time period.

RESULTS

115 coroner's cases were reported and 56 (49%) SADS victims were identified: mean age 32 years, range 7-64 years and 35 (63%) male. 7 of 39 cases (18%) had a family history of other premature sudden deaths (<45). The estimated mortality from SADS was 0.16/100 000 per annum (95% CI 0.12 to 0.21), compared with an official mortality of 0.10/100 000 per annum for International Classification of Diseases 798.1 (sudden death, cause unknown-instantaneous death) or 1.34/100 000 per annum for unascertained causes of death.

CONCLUSIONS

Deaths from SADS occur predominantly in young males. When compared with official mortality, the incidence of SADS may be up to eight times higher than estimated: more than 500 potential SADS cases per annum in England. Families with SADS carry genetic cardiac disease, placing them at risk of further sudden deaths. SADS should therefore be a certifiable cause of death prompting specialised cardiological evaluation of families.

Sudden, unexpected cardiac or unexplained death in England: a national survey

BACKGROUND

Post-mortem examinations of adults who were apparently healthy but died suddenly and unexpectedly sometimes reveal no morphological abnormalities to explain their deaths. The frequency of such unexplained deaths in relation to other causes of sudden cardiac death is not known.

AIM

To estimate the frequency of sudden unexpected cardiac or unexplained death in England.

DESIGN

Prospective survey using a stratified random sample of 83 of the 132 H.M. Coroner's jurisdictions in England.

METHODS

Consecutive White Caucasians, aged 16-64 years, with no medical history of cardiac disease, seen alive within 12 h of death, on whom autopsy found either a cardiac or no identifiable cause of death, were included. The coroner's officer sent a copy of the post-mortem report and a completed case registration form to the investigators, with tissue samples.

RESULTS

Sixty-seven (81%) coroners participated, each maintaining prospective surveillance for 4 months. Of 692 ascertained cases, case registration forms were received for 650 (94%), post-mortem reports for 682 (99%), blood samples for 569 (82%), myocardial slices for 517 (75%) and whole hearts for 47 (7%). In cases with myocardial tissue, death was ascribed to ischaemic heart disease in 465 (82.4%). In 43.1% the ischaemia was acute, in 19.1% there was myocardial scarring but no acute ischaemia, and 20.2% had coronary atheroma only. Death was due to left ventricular hypertrophy in 32 (5.7%), to other cardiac causes in 30 (5.3%) and in 23 (4.1%) there was no clear cause. Those with cardiac causes were 81% male, median ages 55.9 (male) and 56.6 (female) years. The 23 unexplained deaths were 57% female, median ages 40.5 (male) and 54.9 (female) years. The estimated annual frequency of sudden unexpected death due to cardiac or unidentified causes, in English adults of employment age, was 11/100,000 (3481 annual deaths).

DISCUSSION

In 4.1% of sudden unexpected deaths under 65 years, no cause was found. Until it becomes accepted practice to identify these cases by a name, such as Sudden Adult Death Syndrome (SADS), it will not be possible to study their aetiology systematically.

Gender differences in the management and outcome of patients with acute coronary artery disease

STUDY OBJECTIVE

s: To compare the clinical management and health outcomes of men and women after admission with acute coronary syndromes, after adjusting for disease severity, sociodemographic, and cardiac risk factors.

DESIGN

Prospective national survey of acute cardiac admissions followed up by mailed patient questionnaire two to three years after initial admission.

SETTING

Random sample of 94 district general hospitals in the UK.

PATIENTS

1064 patients under 70 years old recruited between April 1995 and November 1996.

MAIN RESULTS

Of the 1064 patients recruited, 126 (11.8%) died before follow up. Of the 938 survivors, 719 (76.7%) completed a follow up questionnaire. There were no gender differences in the use of cardiac investigations during the index admission or follow up period. However, male patients with hypertension were more likely to undergo rehabilitation compared with female hypertensive patients (OR 2.01, 95% CI 0.85 to 4.72). Men were also more likely to undergo coronary artery bypass grafting (CABG) than women (OR 1.90, 95%CI 1.21 to 3.00), but there was no gender difference in the use of revascularisation overall (p=0.14). An indirect indication that the gender differences in CABG were not attributable to bias was provided by the lack of gender differences in health outcomes, which implies that patients received the care they needed.

CONCLUSIONS

Despite the extensive international literature referring to a gender bias in favour of men with coronary heart disease, this national survey found no gender differences in the use of investigations or in revascularisation overall. However, the criteria used for selecting percutaneous transluminal coronary angioplasty compared with CABG requires further investigation as does the use of rehabilitation. It is unclear whether the clinical decisions to provide these procedures are made solely on the basis of clinical need.

Difference in the mortality of the CABRI diabetic and nondiabetic populations and its relation to coronary artery disease and the revascularization mode

In diabetics with coronary artery disease (CAD), there remains uncertainty as to whether revascularization by percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass surgery (CABG) is preferable. To address this, 4-year mortality and level of pre- and postrevascularization angiographic CAD (measured by a series of coronary scores) were compared between both diabetics and nondiabetics and between revascularization modes in the Coronary Angioplasty versus Bypass Revascularization Investigation population as a whole, and then substratified by diabetic status and then by procedure to which they were randomized. The 1,054 randomized subjects contained 125 diabetics (11.9%) who had significantly greater mortality than nondiabetics (RR 2.19, p = 0.001). Among diabetics or nondiabetics, there was no significant mortality difference between those randomized to PTCA versus those to CABG. Diabetics randomized to PTCA and those to CABG had higher mortalities than respective nondiabetics; the association reached significance only in the former (RR 2.41, p = 0.002). All subgroups had similar prerevascularization CAD. Postrevascularization residual CAD was consistently significantly greater in PTCA than in respective CABG subgroups. Most measurements of CAD were greater in diabetic than in nondiabetic subgroups, but none was significant. In the Coronary Angioplasty versus Bypass Revascularization Investigation, diabetics had double the mortality of nondiabetics; this difference was statistically significant both for the entire population and for those randomized to PTCA, but not for those randomized to CABG. Among diabetics or nondiabetics, there was no significant mortality difference between PTCA and CABG. The higher diabetic mortality was more likely related to more rapid disease progression than to greater postrevascularization disease.

The effect of adjusting for baseline risk factors and post revascularisation coronary disease on comparisons between coronary angioplasty and bypass surgery

BACKGROUND

In CABRI at 1 year PTCA was associated with greater repeat revascularisation and angina (but not myocardial infarction or death). We determined whether adjusting for baseline risk factors and post revascularisation coronary disease offsets this disadvantage of PTCA.

METHODS

In the CABRI population the crude association of revascularisation mode (i.e. PTCA or CABG) with four clinical outcome (i.e. mortality, myocardial infarction, repeat revascularisation and angina) was adjusted for the baseline risk factors using a logistic regression model for each clinical outcome. A number of measures of angiographic coronary disease were used to assess post revascularisation coronary disease. One at a time, each of these measures was added to each of the four outcome models, to adjust for post revascularisation coronary disease.

RESULTS

Comparing adjusted and crude unadjusted association of PTCA with repeat revascularisation there was an increase from 12.8 (P<0.0005) (crude relative risk) to 16.7 (P<0.0005) (adjusted odds ratio), with angina, from 1.89 (P=0.001) to 1.98 (P<0.0019), and with mortality from 1.84 (P=0.092) to 2.15 (P=0.060). PTCA was not significantly associated with myocardial infarction, either crudely or after adjustment.

CONCLUSION

Adjusting for baseline risk factors and post revascularisation coronary disease tended to strengthen rather than weaken associations between PTCA and 1 year mortality, repeat revascularisation and angina at 1 year.

Cardioinhibition during tilt testing identifies patients who may benefit from pacing

This study examined whether the various hemodynamic collapse patterns observed during tilt testing in patients with suspected neurocardiogenic syncope are relevant when planning therapy, particularly whether a predominantly cardioinhibitory response predicts a beneficial response from pacing.

METHODS

The effects of temporary atrioventricular (A-V) sequential pacing were studied during tilt testing in 34 patients 48.2 +/- 18.5 years of age. The patient population was divided into a cardioinhibitory group (VASIS classes 2A and 2B) or mixed group (VASIS classes 1 and 3) according to their response to baseline tilt testing. The test was then repeated during A-V pacing with rate hysteresis. A positive response to A-V pacing was defined as a > or = 30-second increase between onset of symptoms and syncope, or mitigation of symptoms compared with the baseline tilt test.

RESULTS

The study protocol was not successfully completed in three patients. Among the remaining 31 patients, a baseline cardioinhibitory response was observed in 17, and a mixed response in 14 patients. A-V sequential pacing was successful in 13 of 17 patients with a cardioinhibitory response versus 5 of 14 patients with a mixed response (P = 0.024).

CONCLUSION

The presence of a predominantly cardioinhibitory collapse pattern (VASIS 2A and 2B) during baseline tilt testing doubled the likelihood of successful temporary A-V sequential pacing, and may identify patients with neurocardiogenic syncope most likely to benefit from permanent dual chamber pacing.

Relation between coronary artery disease, baseline clinical variables, revascularization mode, and mortality. CABRI Participants. Coronary Angioplasty vs. Bypass Revascularisation Investigation

The Coronary Angioplasty vs. Bypass Revascularisation Investigation (CABRI) trial comparing percutaneous transluminal coronary angioplasty (PTCA) with coronary artery bypass grafting did not show a difference in mortality with either procedure. Nonrandomized studies suggest that coronary artery disease (CAD) severity and distribution influences outcome. In the present study we explored the effect of prerevascularization CAD on 1-year mortality in the CABRI population, while adjusting for other baseline variables. Of the 1,054 patients recruited, there were sufficient angiographic results to derive the CAD scores in 974 (92.4%). Of these 974, there were 32 deaths. A number of CAD scores, both weighted for proximal disease (Duke and Leaman) and nonweighted, were used. These scores were then cross-tabulated against mortality. Demographic and clinical variables were also cross-tabulated against mortality and used to derive an initial logistic regression model to predict mortality. The effect of adding each of the CAD scores to this initial model was then assessed. After inclusion of the CAD scores, the best model was: (1) presence of peripheral vascular disease (odds ratio [OR] 3.89, p = 0.0025), (2) previous cerebrovascular accident (OR 2.86, p = 0.043), (3) older age (OR 1.05, p = 0.039), (4) a higher Duke score (OR 2.84, p = 0.0061), and (5) having undergone PTCA (OR 2.12, p = 0.047). In the CABRI population, adjustment for baseline variables, including prerevascularization CAD, revealed significantly higher mortality in those who underwent PTCA than in those who underwent coronary artery bypass grafting.

A national Survey of Acute Myocardial Infarction and Ischaemia (SAMII) in the U.K.: characteristics, management and in-hospital outcome in women compared to men in patients under 70 years

AIMS

To assess the clinical characteristics, management and outcome of women compared to men with acute myocardial infarction or ischaemia.

DESIGN

A prospective clinical survey was made in a random sample of 94 District General Hospitals in the U.K. 1064 patients, <70 years of age, comprising six consecutive females and six consecutive males from each hospital, diagnosed on admission as acute coronary syndromes (myocardial infarction or myocardial ischaemia) were studied. Outcome measures included: admission and final diagnosis, time to delivery of care, inpatient management, complications and clinical outcome.

RESULTS

Five hundred and three women and 561 men were admitted with a diagnosis of acute myocardial infarction or myocardial ischaemia. Women were older, waited longer between seeking and receiving advice, and much less likely to have infarction than men. After adjustment for age, diagnosis and past medical history there were no gender differences in initial and subsequent hospital management, in complications (recurrent ischaemia, arrhythmias, temporary pacing, heart failure), any routine procedure or outcome. Of all patients, 3.4% died in a District General Hospital, 12.2% were transferred to Specialist Cardiac Centres and 84.4% discharged home. Prophylactic medication on discharge was similar for men and women.

CONCLUSION

After adjustment for age, diagnosis and past medical history, although women waited longer between seeking and receiving medical advice, in hospital their assessment, management, complications, outcome and follow-up arrangements were the same as for men. In hospital, management and outcomes were mainly influenced by age, diagnosis (infarction or ischaemia), a past history of coronary disease, but not by gender. This large, nationally representative, survey has found no evidence of important gender difference in the hospital management of acute ischaemic syndromes.

Clinical outcomes, risk stratification and practice patterns of unstable angina and myocardial infarction without ST elevation: Prospective Registry of Acute Ischaemic Syndromes in the UK (PRAIS-UK)

AIMS

To determine characteristics, outcomes, prognostic indicators and management of patients with acute coronary syndromes without ST elevation.

METHODS AND RESULTS

A prospective registry was carried out with follow-up for 6 months after index hospital admission. A history of acute cardiac chest pain was required plus ECG changes consistent with myocardial ischaemia and/or prior evidence of coronary heart disease. Patients with ST elevation or those receiving thrombolytic therapy were excluded. A total of 1046 patients were enrolled from 56 U.K. hospitals. The mean age was 66+/-12 years and 39% were female. The rate of death or non-fatal myocardial infarction at 6 months was 12.2% and of death, new myocardial infarction, refractory angina or re-admission for unstable angina at 6 months was 30%. In a multivariate analysis, patients >70 years had a threefold risk of death or new myocardial infarction compared with those <60 years (P<0.01) and those with ST depression or bundle branch block on the ECG had a five-fold greater risk than those with normal ECG (P<0.001). Aspirin was given to 87% and heparin to 72% of patients in hospital. At 6 months 56% received no lipid-lowering therapy at all. The 6-month rate of coronary angiography was 27% and any revascularization 15%.

CONCLUSIONS

In this cohort there was a one in eight chance of death or myocardial infarction, and a one in three chance of death, new myocardial infarction, refractory angina or re-admission for unstable angina, over 6 months. Age and baseline ECG were useful markers of risk. Aspirin, heparin and statins were not given to about one-sixth, one-third and one-half respectively. Rates of angiography and revascularization appear low. A review of treatment strategies of unstable angina and myocardial infarction without ST elevation is warranted in the U.K. to ensure that patients are receiving optimum treatments to reduce mortality and morbidity.

Trials of angioplasty and surgery: CABRI

The medium term (4-year post randomization) results from CABRI indicate that the principal difference between those randomized to coronary angioplasty and those to coronary surgery has been the much greater need for repeat revascularization in the former. A number of factors may play a role in the greater repeat revascularization rate post coronary angioplasty, these include coronary restenosis, residual coronary artery disease, coronary artery disease progression. In the longer term, graft failure in those who have undergone coronary surgery will be important, and it remains to be seen what the effect of this will be.

Usefulness of tilt test-induced patterns of heart rate and blood pressure using a two-stage protocol with glyceryl trinitrate provocation in patients with syncope of unknown origin

This study assesses the vasovagal collapse pattern changes, i.e, heart rate (HR) and arterial blood pressure (BP) with a 2-stage tilt-test protocol using glyceryl trinitrate (GTN) provocation. With use of the 45-minute 60 degrees head-up Westminster protocol, 102 consecutive patients were studied. Sublingual GTN 300 microg was given to those with a negative passive tilt. Heart rate and BP patterns were classified according to the Vasovagal International Study classification (VASIS) and then compared between those with a positive passive tilt and those with a positive tilt after having been given GTN. Twelve patients did not tolerate tilt testing, and 16 had a negative response despite taking GTN. Thirty-five patients (20 women and 15 men, mean age 45 +/- 21 years [mean +/- SD]) did not take GTN and 38 (26 women and 12 men, mean age 53 +/- 22 years) had positive passive test results. When comparing the VASIS classification between the 2 groups, results showed: type 1, mixed BP and HR decreased without severe bradycardia (31% [passive] vs 54% [with GTN], p = NS); type 2A, BP decreased before HR decreased (20% vs 22%, p = NS); type 2B, HR decreased before or coincident with BP (34% vs 8%, p = 0.003); type 3, BP decreased without HR decrease (9% vs 0%, p = NS); exception 1, chronotropic incompetence (0% vs 13%, p = 0.026); and exception 2, excessive HR increase (6% vs 3%, p = NS). Thus, GTN use increases frequency of positive results from 34% to 73%. Older people with chronotropic incompetence, who may benefit from pacing, were identified. In younger people there was an increase in those with cardioinhibition.

Role of restenosis in determining adverse outcome after coronary angioplasty vs bypass surgery

A group of patients who did not have restenosis after percutaneous transluminal coronary angioplasty (PTCA) was compared with a group receiving coronary artery bypass grafting (CABG). Restenosis only partially accounted for the greater morbidity after PTCA compared with CABG.

Impact of postangioplasty restenosis on comparisons of outcome between angioplasty and bypass grafting. Coronary Angioplasty versus Bypass Revascularisation Investigation (CABRI) Investigators

Restenosis is a major limitation of percutaneous transluminal coronary angioplasty (PTCA). In this study, we assessed the impact of restenosis on PTCA with reference to coronary angioplasty bypass grafting (CABG). In the Coronary Angioplasty versus Bypass Revascularisation Investigation (CABRI) PTCA population, those who had restenosis were defined as those needing a second revascularization at a site revascularized at the initial procedure. The 1-year clinical outcome of the nonrestenotic group (n=437) was compared with those who underwent CABG (n=453). There was no difference in deaths. In the nonrestenotic PTCA group, the incidence of more infarctions was insignificant (relative risk [RR] 1.9, 95% confidence intervals [CI] 0.96 to 3.75, p=0.064), there was a much greater need for repeat revascularization (RR 8.6, CI 5.14 to 14.41, p <0.0005), and patients had a poorer angina status (RR 1.46, CI 1.01 to 2.13, p=0.046). Using 2 measures of coronary disease, the degree of pre- and postrevascularization disease was compared between groups. There were no differences in prerevascularization disease. However, using either measure, residual postrevascularization disease was more frequent in the nonrestenotic PTCA group. Restenosis only partially accounts for the greater morbidity seen after PTCA, compared with CABG, in multivessel disease. The greater likelihood of residual disease post-PTCA may contribute to this greater morbidity.

Differential restenosis rate of individual coronary artery sites after multivessel angioplasty: implications for revascularization strategy. CABRI Investigators. Coronary Angioplasty versus Bypass Revascularisation Investigation

BACKGROUND

Restenosis is a major limitation of angioplasty. In this analysis we assessed the effects of lesion site and quality of dilatation on restenosis rate in the Coronary Angioplasty versus Bypass Revascularization Investigation population who underwent angioplasty.

METHODS

The angiographic quality of the successful angioplasty revascularization at each site was assessed, and the subsequent restenosis rate was determined. Restenosis was defined by the need for a second angioplasty at the initial site or by surgical coronary bypass grafting at or distal to the initial site.

RESULTS

The restenosis rate was unaffected by quality of dilatation but was significantly more common in the proximal left anterior descending artery compared with other sites, whether or not optimal dilatation had been achieved (relative risk 2.0 and 1.9, respectively).

CONCLUSION

Revascularization strategies in multivessel disease should consider the presence or absence of a proximal left anterior descending artery target. Furthermore in studies in which restenosis is an outcome of interest, an allowance should be made for the distribution of target disease.

A British Cardiac Society survey of the potential for the secondary prevention of coronary disease: ASPIRE (Action on Secondary Prevention through Intervention to Reduce Events)

OBJECTIVE

To measure the potential for secondary prevention of coronary disease in the United Kingdom.

DESIGN

Cross sectional survey of a representative sample of coronary patients from a retrospective review of hospital medical records and patient interview and examination.

SETTING

Stratified random sample of 12 specialist cardiac centres and 12 district general hospitals drawn from 34 specialist cardiac centres and 261 district general hospitals in 12 geographic areas in the United Kingdom.

SUBJECTS

2583 patients < or = 70 yr; 25 consecutive males and 25 consecutive females identified retrospectively in each of four diagnostic categories: coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, acute myocardial infarction, and acute myocardial ischaemia without evidence of infarction.

MAIN OUTCOME MEASURES

Risk factor recording and management in medical records; the prevalence and control of risk factors at interview six months after the procedure or event.

RESULTS

Recording of coronary risk factors in patient's records was incomplete and this varied by risk factor. Smoking habit and blood pressure were most completely recorded, whereas a history of hyperlipidaemia and blood cholesterol concentrations were least complete. Risk factor records were more likely to be complete in cardiac centres than in district hospitals. At interview 10% to 27% of patients were still smoking cigarettes and 75% remained overweight, females more severely so. Up to a quarter of patients remained hypertensive, males more severely so than females. Over three quarters had a total cholesterol > 5.2 mmol/l. In patients on medication for blood pressure, cholesterol or glucose, risk factor profiles were little better than in those who were not. Only about one patient in three was taking a beta blocker after infarction. Up to a fifth of patients who had had acute myocardial ischaemia were not taking aspirin at follow up.

CONCLUSIONS

There is considerable potential to reduce the risk of a further major ischaemic event in patients with established coronary disease. This can be achieved by effective lifestyle intervention, the rigorous management of blood pressure and cholesterol, and the appropriate use of prophylactic drugs.

Sudden unexpected cardiac death: methods and results of a national pilot survey

In order to develop a methodology for measuring the occurrence and circumstances of sudden unexpected adult deaths due to cardiac and to unidentified causes throughout England, a stratified random pilot sample of 12 of the 133 coroner's jurisdictions in England was invited to survey prospectively a quota sample of 78 consecutive white Caucasians, aged from 16 to 64 years, with no history of ischaemic heart disease, who were last seen alive within 12 h of being found dead, and for whom a coroner's post-mortem examination found either a cardiac or no identifiable cause of death. Eleven (92%) coroners participated. In a median of 105 days (range 21-169), 65 cases (83% of the quota) were ascertained (54 (83%) males). Of the ascertained cases, registration forms were received on 62 (95%), tissue specimens on 63 (97%), and post-mortem reports on 58 (89%). Death was witnessed in 58%, of which 35% were 'instantaneous'. The median time from symptom onset to death was 40 min. In unwitnessed deaths, the median time since last being seen alive was 90 min. Sixty-eight per cent of all deaths were attended--by a relative in 34%, passer-by (8%), ambulance crew (32%), nurse (11%), doctor (38%), and police (9%). Cardio-pulmonary resuscitation was attempted in 38 of the 42 attended deaths. Sixty-seven per cent were taken ill at home, 12% at work, 12% in a public place, and 10% elsewhere. The certified cause of death was ischaemic heart disease in 89%, in whom coronary thrombosis and/or myocardial damage was absent in 6 cases (9%). In the remainder, the certified cause was hypertensive heart disease (5%), hypertrophic obstructive cardiomyopathy (3%), 'cardiomegaly' (1.5%) and 'sudden cardiac arrhythmia' alone (1.5%). A retrospective audit of coroner's records revealed the median case ascertainment rate was 75%. This approach to surveying sudden unexpected adult death nationally resulted in a high response rate (92%) from coroners, consultant pathologists and their staff, the identification of a large proportion of eligible cases, and complete information in most of the identified cases. In from 2% to 15% of cases, death may have been either purely dysrhythmic or due to a sudden adult death syndrome.

Percutaneous transluminal coronary angioplasty in chronic coronary artery occlusion

OBJECTIVES

This study was conducted to determine the procedural success rate, complication rate and long-term outcome of percutaneous transluminal coronary angioplasty in chronically occluded coronary arteries.

BACKGROUND

Coronary angioplasty of chronically occluded vessels has a lower success rate than has angioplasty of nonoccluded vessels, but it is frequently considered safe because the target vessel is already occluded. The purpose of this study was to determine the reliability of these assumptions at our institution, with the objectives stated above.

METHODS

We identified from the angioplasty data base at our institution 100 consecutive coronary angioplasty procedures performed between 1987 and 1991 for chronic total occlusion, defined as complete occlusion (Thrombolysis in Myocardial Infarction [TIMI] grades 0 and 1 flow) for > or = 3 months. The records of the 95 patients who underwent these procedures were reviewed to determine procedural outcome and medium-term results.

RESULTS

Procedural success was obtained in 47 occluded vessels (47%). Significantly fewer successes were obtained in the right coronary artery (26.8%) than in either the left anterior descending (57.1%) or the left circumflex (45%) coronary artery (p < 0.05). A procedural failure without serious adverse consequences occurred in 45 procedures (45%), but in eight patients (right coronary artery in five, left anterior descending artery in three) attempted recanalization was complicated by extensive coronary dissection with acute myocardial ischemia, and one of these patients died. There were no emergency operations, but elective coronary artery bypass surgery was undertaken in 26 patients (in 3 after extensive dissection, in 7 after an apparently good result and in 16 in whom the procedure failed). At 12 months after the procedure, 64.1% of those with a procedural success were event free compared with 32.6% of those whose procedure was both unsuccessful and uncomplicated (p < 0.025) and 25% of those in whom it was unsuccessful and complicated by coronary dissection (p < 0.025).

CONCLUSIONS

In this series of recanalization of chronically occluded coronary arteries, there was a low procedural success rate, particularly for the right coronary artery. However, when procedural success was obtained, the long-term outlook was good. The overall risk of coronary dissection was comparable to the risk in nonoccluded vessels but was particularly high in the right coronary artery (13%).

A new method of haemodynamic assessment of mitral stenosis in atrial fibrillation: construction of a nomogram

Accurate haemodynamic assessment of mitral stenosis by hydraulic formulas requires measurement of the mean valve gradient and the cardiac output. The calculation is laborious, particularly in the presence of atrial fibrillation when averaged values obtained from multiple beat-to-beat determinations must be used. The relations between valve area, end diastolic gradient, and heart rate in 20 patients with mitral stenosis and atrial fibrillation were examined. In each patient the end diastolic pressure gradient for each cardiac cycle was related linearly to the RR interval of that cycle, and this relation was unchanged on exercise. The slope (S) and intercept (I) of this relation correlated with the degree of mitral stenosis as measured by the Gorlin valve area. The regression equations describing these relations were then used to construct a nomogram relating end diastolic pressure gradient to mitral valve area at different heart rates. When the nomogram was applied to catheterisation data from a further 30 patients the results correlated well with direct calculation of valve area by the Gorlin formula. The nomogram is simple to use, does not require measurement of cardiac output, and is independent of heart rate so that it is unnecessary for the patient to exercise during catheterisation.

Laser angioplasty with a pulsed NdYAG laser: early clinical experience

Since December 1986, 40 laser angioplasty procedures have been performed using the energy from a pulsed NdYAG laser, delivering near infrared light (1064 nm) in 100-microseconds pulses of approximately 300 mJ per pulse, directly through a transparent sapphire tipped device. All patients had total occlusion of the superficial femoral artery and symptoms severe enough to warrant surgery, with ulceration or gangrene in eight, rest pain in 14 and severe claudication interfering with life-style in the others. The device was introduced through an antegrade puncture of the superficial or common femoral artery and laser recanalization was followed by attempted balloon angioplasty in all cases. Occlusions were a median length of 15 cm (range 2-35 cm); ten patients had previously undergone failed attempts at conventional balloon angioplasty and four had occluded femoropopliteal grafts. Thirty-seven legs of 34 patients were treated with an average of 60 J (range 10-235 J) with successful recanalization in 27 and immediate reocclusion in seven. The 20 successful recanalizations have been followed up for up to 24 months (median 7 months) with only one late occlusion at 5 months. Failed recanalization was due to poor transmission by the delivery device in the early part of the series (five cases), repeated passage of the device down a collateral branch (four cases), dissection at the site of previous surgery (two cases) or no apparent reason (two cases). Immediate reocclusion was due to very poor run off in patients with severely ischaemic limbs (three cases) or technical difficulties with balloon dilatation (two cases). Complete symptomatic relief was obtained in all the cases of radiologically successful laser angioplasty. Early surgery was required in one case following reocclusion of the artery when an angioplasty balloon failed to deflate, and one patient suffered a skin reaction thought to be due to inadequate removal of the sterilizing solution. A different sterilizing procedure is now followed. Laser angioplasty can reduce the number of patients requiring bypass surgery and improvements in the device and access methods may reduce the number of untreatable cases.

Assessment of a new device for laser angioplasty

Experimental work has shown that a transparent laser device delivering pulsed energy to an artery results in a smaller area of surrounding damage than does an opaque device with a continuous wave laser. The combination of a transparent ball-tipped device with a pulsed Nd-YAG laser has been investigated. The system delivers pulses of 100 microseconds at a rate of 10 Hz and average energy of 0.5 J per pulse with an energy loss of 5-10% between the output at the laser rail and the fibre tip. The dose/response was measured and showed that on normal aorta under saline the device produces craters with a depth of 5 microns/J and 1.5 mm radius. There is a 100% increase in dose response with diseased aorta and a 50% increase when exposure is carried out under blood. The effect of a varying angle of incidence upon the arterial wall has been measured. Angulation of the device at 10 degrees from the perpendicular reduces the crater depth to 50%, as compared with a 50% reduction at 60 degrees using a bare fibre. As estimated with a thermal camera in air, the device heats up to a maximum of 50 degrees C during a 50 J exposure, compared to 110 degrees C after 5 J for the sapphire device. Artificial circulation experiments were carried out using diseased femoral vessels occluded by a ligature. The new system recanalised 100% of occlusion in straight vessels, and 40% of occlusions in curved vessels at a radius of 2.5 cm.(ABSTRACT TRUNCATED AT 250 WORDS)

Perforation thresholds and safety factors in in vivo coronary laser angioplasty

Laser angioplasty can cause early (acute perforation) or late (stenosis or aneurysm) complications. To find how much intravascular laser energy can be delivered via a 100 microns core optical fibre passed down a balloon angioplasty catheter without causing angiographic abnormalities up to 10 days later, argon laser energy was delivered percutaneously under radiographic screening to the coronary circulation of 12 normal closed chest dogs. With the balloon inflated, sequential laser pulses were delivered to the same site. Angiograms were recorded before, immediately, and again at one week, after laser delivery. There were two laser-induced perforations (both fatal). Mechanical perforation with the 100 microns fibre occurred four times, but there were no haemodynamic sequelae. To find the acute perforation threshold of similar sized arteries to energy delivered via the bare 100 microns core fibre, the tip of which was held in contact with the luminal surface, 32 argon laser pulses were delivered transluminally in vivo to separate sites in normal rabbit iliac and canine coronary arteries. The acute perforation threshold with energy delivered via the angioplasty catheter lay between 6 and 10 J and that without the balloon angioplasty catheter lay between 3 and 4 J. After delivery of up to 6 J via a balloon angioplasty catheter, there were no angiographic abnormalities at one week. Fibre optic transluminal delivery of laser energy may improve the primary success rate of, and perhaps widen the indications for, coronary angioplasty.

The physical properties of tissue ablation with excimer lasers

The current controversy regarding the interaction between the output of the excimer laser and human tissue concerns the relative importance of photothermal and photoablative effects. Two experiments using an excimer laser on vascular tissue, aimed at defining the precise laser-tissue interaction, were performed. The experiments argue strongly in favor of photoablative effects that result from multiple photon interactions with ablated tissue.

Arterial healing in the dog after intraluminal delivery of pulsed Nd-YAG laser energy

The application of laser energy to percutaneous recanalization of diseased blood vessels is of interest to vascular surgeons and radiologists. We have examined the effect of pulsed infrared light from a 100 microseconds pulsed Nd-YAG laser on the dog aorta in order to determine the dose response, perforation thresholds and healing properties in vascular tissue. We used 100 microseconds pulses of 0.5 J energy at 10 Hz repetition rate via a 400 micron optical fibre to make 205 craters in 10 dogs at total energies of 5-25 J. The perforation threshold was 15 J in six animals and 20 J in four. The dose response was linear at 10 micron tissue vaporized per Joule delivered. Animals were killed immediately and at intervals of 24 h, 4, 7 and 10 days, 2, 3 and 6 weeks, and 3 and 6 months. Material was retrieved for histology and examined by light and scanning electron microscopy. The tissue exhibited features of laser damage that were less marked than those seen with continuous wave lasers; there was less heat damage surrounding the craters which healed well, even after perforation. This laser is likely to be suitable for human laser angioplasty provided the energy is given in increments of 15 J or less.

Optical transmission of normal and atheromatous arterial wall: a spectral analysis

In laser angioplasty one of the factors influencing the immediate damage (and therefore the risk of acute arterial perforation) is the optical absorption characteristics of the target tissue. In an attempt to evaluate the differences in optical absorptive properties, the transmission spectrograms of samples of normal and atheromatous human postmortem aortic wall were measured over the visible spectrum. Optical transmission varied inversely with sample thickness and directly with wavelength through both normal and atheromatous samples. Over the whole visible spectrum atheromatous tissue transmitted less per unit thickness than normal tissue. This differential effect was, however, most pronounced at 500 nm, where atheromatous tissue transmitted light 5-10 times less strongly than normal aortic wall. Such wavelength dependent differential optical absorption could provide a means for the selective photovaporisation of atheroma in laser angioplasty.