Shrinkage of human coronary arteries is an important determinant of de novo atherosclerotic luminal stenosis: an in vivo intravascular ultrasound study

Objective—To assess the occurrence of arterial remodelling types and its relation with the severity of luminal stenosis in atherosclerotic coronary arteries.
Patients and methods—Twenty one de novo coronary lesions of 20 patients, who were scheduled for percutaneous transluminal coronary angioplasty (PTCA), were investigated with intravascular ultrasound before PTCA. Local arterial remodelling at the lesion site was studied by measuring the cross sectional area circumscribed by the external elastic lamina (EEL) relative to the reference site: (EEL area lesion/reference EEL area) × 100%. Three groups were defined. Group A: relative EEL area of less than 95% (shrinkage), group B: relative EEL area between 95% and 105% (no remodelling), group C: relative increase in EEL area of more than 105% (compensatory enlargement).
Results—All three types of remodelling were observed at the lesion site: group A (shrinkage) n = 8, group B (no remodelling) n = 5, group C (compensatory enlargement) n = 8. The mean (SD) relative EEL area at the lesion site in group A and C was 83(9)% and 132(30)%, respectively. In group A, 33% of the luminal area stenosis at the lesion site was caused by shrinkage of the artery. In contrast, group C showed that 87% of the plaque area did not contribute to luminal area stenosis because of compensatory arterial enlargement.
Conclusions—These results show that both compensatory enlargement and paradoxical shrinkage occurs in the atherosclerotic coronary artery. Next to plaque accumulation, the type of atherosclerotic remodelling is an important determinant of luminal narrowing.

Keywords: coronary arteries; atherosclerosis; remodelling; intravascular ultrasound     

Magnesium causes nitric oxide independent coronary artery vasodilation in humans

OBJECTIVE—To determine how magnesium affects human coronary arteries and whether endothelium derived nitric oxide (EDNO) is involved in the coronary arterial response to magnesium.
DESIGN—Quantitative coronary angiography and Doppler flow velocity measurements were used to determine the effects of the nitric oxide synthase inhibitor N^G-monomethyl-L-arginine (L-NMMA) on magnesium induced dilation of the epicardial and resistance coronary arteries.
SETTING—Hiroshima University Hospital a tertiary cardiology centre.
PATIENTS—17 patients with angiographically normal coronary arteries.
INTERVENTIONS—Magnesium sulfate (MgSO₄) (0.02 mmol/min and 0.2 mmol/min) was infused for two minutes into the left coronary ostium before and after intracoronary infusion of L-NMMA.
MAIN OUTCOME MEASURES—Diameter of the proximal and distal segments of the epicardial coronary arteries and coronary blood flow.
RESULTS—At a dose of 0.02 mmol/min, MgSO₄ did not affect the coronary arteries. At a dose of 0.2 mmol/min, MgSO₄ caused coronary artery dilation (mean (SEM) proximal diameter 3.00 (0.09) to 3.11 (0.09) mm; distal 1.64 (0.06) to 1.77 (0.07) mm) and increased coronary blood flow (79.3 (7.5) to 101.4 (9.9) ml/min, p < 0.001 v baseline for all). MgSO₄ increased the changes in these parameters after the infusion of L-NMMA (p < 0.001 v baseline).
CONCLUSIONS—Magnesium dilates both the epicardial and resistance coronary arteries in humans. Furthermore, the coronary arterial response to magnesium is dose dependent and independent of EDNO.


Keywords: coronary artery; coronary blood flow; magnesium sulfate; nitric oxide     

Validation of an automated technique for determining the mechanical characteristics of coronary arteries during balloon angioplasty: laboratory assessment with necropsy segments

OBJECTIVES: To develop a technique for automatic inflation of a percutaneous transluminal coronary angioplasty (PTCA) balloon, with continuous measurement of the balloon pressure and volume; to validate the technique for determining the mechanical characteristics of coronary arteries. METHODS: During necropsy examination of the hearts of nine patients, 17 coronary artery samples were obtained for histological examination. A PTCA balloon was inserted into each artery, and the balloon pressure and volume were measured continuously during four repeat automatic inflations of the balloon. RESULTS: Of the 17 arteries, eight showed elastic, six plastic, and three fracture pressure-volume deformation characteristics. For the plastic deformations, the first inflation required a higher pressure than subsequent repeat inflations of 82 (61) kPa (mean (SD), range 25 to 175 kPa). For the three in the fracture group, the pressure drop because of the fracture occurred between 210 and 540 kPa. Two of these three showed a tear on visual inspection, and the other showed disruption of the intimal plaque on blinded histological examination. Of the six with plastic deformation characteristics alone, one showed a tear, and on histological examination two others showed splitting of the internal and external elastic lamina and one showed separation of intima and media. None in the elastic group showed any of these characteristics. CONCLUSIONS: Plastic and fracture deformation characteristics could be differentiated from elastic characteristics. Visual or histological evidence of fracturing was present in all three arteries identified during angioplasty as having pressure-volume fracture characteristics.     

Myocardial infarction in young people with normal coronary arteries

Myocardial infarction occurring in young people with angiographically normal coronary arteries is well described but the pathophysiology of this condition remains unknown. Coronary artery spasm in association with thrombus formation and minimal atheromatous disease or spontaneous coronary artery dissection are possible causes. Two young men presented with severe chest pain after acute alcohol intoxication and each sustained an extensive anterior myocardial infarction. Investigations including intravascular ultrasound showed no evidence of atherosclerotic coronary artery disease. Coronary artery spasm associated with acute alcohol intoxication as well as a prothrombotic state and endothelial damage related to cigarette smoking may be mechanisms leading to acute myocardial infarction in these cases. Acute myocardial infarction occurs in young persons with normal coronary arteries and the diagnosis should be considered in young patients presenting with severe chest pain, particularly those abusing cocaine or alcohol, so that reperfusion therapy can be initiated promptly.

Keywords: myocardial infarction;  coronary vasospasm;  alcohol;  intravascular ultrasound     

Coronary flow reserve in the contralateral artery increases after successful coronary angioplasty in patients with spontaneously visible collateral vessels

Objective—To test the hypothesis that coronary flow reserve could increase in the angiographically normal contralateral artery after successful coronary angioplasty of an ipsilateral coronary artery.
Design—Coronary flow reserve was estimated using a Doppler flow guide wire, by giving intracoronary adenosine in the contralateral artery, before and 15 minutes after the end of angioplasty.
Setting—Tertiary referral centre.
Patients—31 patients, mean (SD) age 56 (11) years, with stable angina and single vessel disease, undergoing angioplasty of the right coronary or the left anterior descending artery.
Results—In the contralateral artery baseline average peak velocity was 21 (9) cm/s before angioplasty and decreased to 12 (6) cm/s after (p < 0.005), while hyperaemic average peak velocity was 47 (19) cm/s before and decreased to 34 (15) cm/s after (p < 0.005). However, coronary flow reserve in the contralateral artery was 2.4 (0.7) before angioplasty and increased to 2.9 (0.6) after (p < 0.05). The contralateral coronary flow reserve after angioplasty increased by 0.8 (0.4) in 11 patients with visible collaterals before angioplasty and by 0.3 (0.6) in the remaining patients without visible collaterals (p < 0.05). Blood pressure and heart rate were unchanged after the procedure.
Conclusions—Coronary flow reserve in an angiographically normal contralateral artery increases after successful coronary angioplasty of the ipsilateral artery in patients with spontaneously visible collateral vessels before the procedure.

Keywords: coronary flow reserve; contralateral coronary artery; angioplasty     

S-Nitrosoglutathione inhibits platelet activation and deposition in coronary artery saphenous vein grafts in vitro and in vivo

Objective—To investigate platelet activation and deposition in human saphenous vein and internal mammary artery grafts following coronary artery bypass in vitro and in vivo, as well as inhibition of activation by the platelet selective nitric oxide donor S-nitrosoglutathione (GSNO).
Design—Controlled in vitro and in vivo studies.
Setting—Tertiary cardiac centre.
Patients—24 patients undergoing coronary artery bypass surgery requiring vein and artery grafts.
Interventions—In vitro: human platelet rich plasma was perfused through segments of vein and artery, with or without GSNO 10^-6 M, and the platelet count was measured in the effluent. In vivo: indium-111 labelled antibody against the platelet α granule protein GMP-140 was injected at the end of coronary bypass grafting and γ counts were compared between vein and artery grafts with or without systemic infusion of GSNO (40 nmol/min).
Results—In vitro: platelet count in perfused vein (< 70% of baseline) decreased more than in artery segments (89-94% of baseline) (p < 0.001). The platelet count was unchanged with GSNO in vein and artery segments. In vivo: γ counts were greater at all time points over vein than artery grafts (p < 0.05), and were reduced by infusion of GSNO (p < 0.05).
Conclusions—Platelet activation is greater in vein than in artery grafts in vitro and in vivo. Activation, which contributes to early vein graft failure, was inhibited by GSNO.

Keywords: coronary artery bypass surgery;  platelet activation;  S-nitrosoglutathione;  ischaemic heart disease     

Restenosis after elective coronary balloon angioplasty in patients with end stage renal disease: a case-control study using quantitative coronary angiography

Objective—To assess the rate of angiographic restenosis in patients with end stage renal disease after elective coronary angioplasty.
Design—A retrospective case-control study of 20 patients with end stage renal disease and 20 sex and age matched controls without renal disease, who had undergone primarily successful coronary angioplasty. Control coronary angiography was performed regardless of worsening or renewed incidence of anginal symptoms.
Main outcome measures—Group comparison of coronary morphology, as evaluated by quantitative coronary angiography, and of cardiovascular risk factors.
Results—The rate of angiographic restenosis was 60% in patients with renal disease and 35% in controls. In patients with end stage renal disease the following differences (mean (SD) were found versus controls: raised plasma fibrinogen (483 (101) v 326 (62) mg/dl, p < 0.001); raised plasma triglyceride (269 (163) v 207 (176) mg/dl, p < 0.01); smaller diameter of the coronary reference segment (2.59 (0.87) v 2.90 (0.55) mm, p < 0.10); smaller minimum luminal diameter of the dilated stenosis (0.77 (0.46) v 0.97 (0.27) mm, p < 0.05). Discriminant analysis showed that minimum luminal diameter before angioplasty (r = −0.79) and fibrinogen (r = +0.34) had the highest statistical association with restenosis.
Conclusions—The high rate of angiographic restenosis in patients with end stage renal disease seems to be related to the size of the vessel dilated and to an increased prothrombotic risk, as indicated by higher fibrinogen concentrations.

Keywords: renal disease;  coronary artery disease;  coronary angioplasty;  restenosis     

Effects of inhibition of nitric oxide synthesis in patients with coronary artery disease and stable angina

AIMS: Inhibition of nitric oxide synthesis causes a decrease in thebasal diameter of normal distal epicardal coronary arteriesin normal subjects. The effects of inhibition of nitric oxidein atheromatous coronary arteries is unknown. This study assessedthe effects of the inhibition of nitric oxide synthesis in epicardialcoronary arteries in patients with coronary artery disease. METHODS AND RESULTS: The effects of an intracoronary infusion of N^G-monomethyl-L-arginine(LNMMA, an inhibitor of nitric oxide synthesis), were studiedin 13 patients with chronic stable angina and coronary arterydisease. The diameter of angiographically normal proximal anddistal segments and coronary stenoses was measured by quantitativeangiography. In response to an LNMMA infusion of 16 µmolmin^–1 for 4 min there was a significant reduction (P<0·01)in the luminal diameter of the distal segments of diseased arteries(from 1·32 ± 0·07 to 1·17 ±0·06 mm) and at the site of stenosis (from 1·15± 0·22 to 1·06 ± 0·20 mm),but no change (P=NS) in the luminal diameter of the proximalsegments (from 3·16 ± 0·12 to 3·08± 0·14 mm) of diseased arteries. CONCLUSIONS: The average effect of inhibition of basal nitric oxide synthesisin epicardial coronary arteries in patients with stable anginaand coronary artery disease was only distal constriction. Coronarystenoses constricted at the highest LNMMA concentration.     

Complex stenosis morphology and vasomotor responses to inhibition of nitric oxide synthesis

OBJECTIVE—To assess the relation between coronary vasomotor effects of N^G-monomethyl-L-arginine (LNMMA) administration and coronary stenosis morphology, length, and severity in patients with stable angina.DESIGN—In 28 patients (24 male, four female) with coronary artery disease and chronic stable angina, intracoronary normal saline and 4 µmol/min LNMMA were infused for four minutes each, followed by an intracoronary bolus of 250 µg glyceryl trinitrate. Coronary stenoses were classified as concentric (smooth), eccentric (smooth), or complicated (irregular). The diameters of these stenoses and their adjacent reference proximal segments were measured by quantitative angiography.RESULTS—During LNMMA infusion a significantly larger proportion of complicated stenoses than concentric and eccentric stenoses constricted by ? 5% (p < 0.01) and the magnitude of vasoconstriction was greater in complicated than in concentric and eccentric stenoses (p < 0.05). For complicated stenoses the magnitude of constriction (in mm) with reference to normal saline was greater than that of the concentric and eccentric stenoses (p < 0.05), whereas concentric and eccentric stenoses constricted similarly. Irrespective of the type of morphology, there was a correlation (p < 0.05) between both the severity and the length of stenoses and the magnitude of vasoconstriction to LNMMA. A similar proportion of concentric, eccentric, and complicated stenoses showed ? 5% increase in diameter with glyceryl trinitrate, and the magnitude of the response was similar in the three groups.CONCLUSIONS—In patients with coronary artery disease, the response to LNMMA is greater when stenosis morphology is complex, indicating greater nitric oxide activity. This provides further evidence that plaques with complex morphology are in an active state.     

Aneurysms and pseudoaneurysms of saphenous vein coronary artery bypass grafts

Aneurysms of saphenous vein grafts to coronary arteries are unusual complications of coronary artery bypass graft (CABG) surgery. Three patients (men aged 47, 62, and 68 years) are presented with spontaneous chest pains 10, 21, and 17 years after CABG surgery. In one case, the saphenous vein graft had eroded into the right atrium and had established a fistula between the graft and the right atrium. Diagnosis of saphenous vein graft aneurysms was confirmed by echocardiography, computed tomography or magnetic resonance imaging, and by arteriography. Two patients were treated surgically, the third by percutaneous coil embolisation followed by balloon angioplasty of the right coronary artery.

Keywords: aneurysm;  pseudoaneurysm;  saphenous vein grafts;  coronary artery bypass graft     

Hibernating myocardium caused by isolated, radiation induced left main stem coronary artery stenosis

A 45 year old man presented with a five week history of worsening exertional dyspnoea and orthopnoea. He had also noted mild, bilateral ankle swelling. The patient had been diagnosed with stage III Hodgkin's lymphoma in 1968 at the age of 21. During the same year he underwent total nodal irradiation followed by chemotherapy in 1971. He had remained entirely asymptomatic over the course of the next 24 years with no evidence of relapse. Cardiac catheterisation undertaken soon after admission revealed a tight left main stem stenosis with a left dominant system. Left ventriculogram showed severe, global hypokinesia, and raised left ventricular end diastolic pressure (22 mm Hg). Urgent coronary artery bypass graft surgery was carried out. He made an uncomplicated recovery and his condition improved sufficiently to allow discharge eight days following the procedure. His heart failure slowly resolved and repeat transthoracic echocardiogram performed six months after surgery showed an unequivocal improvement in left ventricular function. Left ventricular ejection fraction continued to improve and increased from 23% at two months to 42% at two years. He currently remains entirely asymptomatic off all medication.

Keywords: left main stem stenosis;  radiation induced coronary artery disease;  hibernating myocardium     

Endoluminal vessel reconstruction by stent placement in patients with obstructive coronary artery disease who are poor surgical candidates

Objective—To investigate the safety and efficacy of endoluminal vessel reconstruction by intracoronary stenting in patients with single or multivessel disease who have been turned down for surgical revascularisation.
Design—An observational, single centre trial of consecutive patients being followed up clinically.
Setting—Tertiary referral centre.
Patients—43 patients treated between 1995 and 1996 with a clinical follow up period of at least six months.
Main outcome measures—Acute procedural success following intervention (defined as a residual stenosis of < 30% with normal antegrade flow and without acute clinical complications); major adverse clinical events (death, myocardial infarction, repeat intervention, clinical restenosis); and functional status during follow up.
Results—Acute procedural success was achieved in 39 patients. Failures resulted from a refractory no reflow phenomenon with Q wave myocardial infarction (two patients), and from subacute stent thrombosis (one patient) and saphenous vein graft rupture at stent site (one patient), both manifesting by non-Q wave myocardial infarction. During a follow up period of 17 (8) months (mean (SD)), three of these patients died. Clinical restenosis was treated by repeat percutaneous intervention in 11 patients, while 28 patients remained asymptomatic. On a Kaplan-Meier estimate, the proportion of patients without adverse clinical events at two years was 65%.
Conclusions—Percutaneous reconstruction of diseased coronary arteries in patients with single or multivessel disease turned down for surgical revascularisation may be considered as a valuable treatment option. On follow up, more events seem to be encountered than after elective de novo stenting of discrete coronary lesions. This is probably related to higher clinical restenosis rates.

Keywords: coronary artery disease;  stents;  restenosis     

Nitrate induced coronary vasodilatation: differential effects of sublingual application by capsule or spray

Background—Sublingual nitroglycerin (glyceryltrinitrate, GTN) capsules or isosorbide dinitrate (ISDN) spray are routinely used to treat anginal attacks and to vasodilate maximally the epicardial coronary arteries during coronary angiography.
Objective—To compare the coronary vasodilatory effects of GTN capsules and ISDN spray with those induced by intracoronary GTN using quantitative coronary angiography.
Design—96 patients (79 men and 17 women; median age 59 years) were randomised to four groups to receive either a sublingual capsule containing 0.8 mg GTN or two puffs of spray delivering 0.8 mg ISDN, followed or preceded by an intracoronary bolus of 0.2 mg GTN used as reference for maximal vasodilatation.
Results—There was a significant increase in the mean diameter of coronary arteries in angiographically normal segments in patients who received either intracoronary GTN (groups 1 and 2) or ISDN spray (group 4) as a first application (group 1, 0.46 mm, +17%, (baseline vessel diameter 100%), p < 0.001; group 2, 0.45 mm, +13%, p < 0.001; group 4, 0.47 mm, +13%, p < 0.05). Patients who received a sublingual GTN capsule as the first application mode (group 3) had no significant change in epicardial vessel diameter (0.10 mm, +5%, p = 0.3).
Conclusions—Sublingual ISDN spray may be more efficacious than sublingual GTN capsules in certain patients with anginal attacks. ISDN spray should be preferred over capsules in coronary angiographic procedures.

Keywords: angiography;  isosorbide dinitrate;  nitroglycerin;  vasodilatation;  angina     

冠状动脉慢血流患者一氧化氮和内皮素1浓度的变化

目的探讨冠状动脉慢血流(coronary slow flow,CSF)患者的血管内皮功能。方法选择因胸痛行冠状动脉造影的患者40例,根据造影结果分为CSF组20例和对照组20例。2组分别于静息和多巴酚丁胺负荷试验结束时立即抽取血标本,检测血浆内皮素1、血清NO浓度,并进行比较。结果 CSF组静息时血浆内皮素1浓度较对照组升高,但差异无统计学意义(P>0.05),而药物负荷试验后血浆内皮素1浓度较对照组明显升高,差异有统计学意义[(37.60±6.93)ng/L vs(14.16±5.73)ng/L,P<0.01]。CSF组静息时和药物负荷试验后血清NO浓度均明显低于对照组,差异有统计学意义[(42.36±9.72)μmol/L vs(50.39±9.77)μmol/L,(24.88±9.28)μmol/L vs(61.06±8.20)μmol/L,P<0.01)]。结论 CSF患者无论静息或者药物负荷状态下均存在内皮素1及NO平衡失调,负荷状态下这种平衡失调现象更加明显。     

Myocardial ischaemia in a case of a solitary coronary ostium in the right aortic sinus with retroaortic course of the left coronary artery: documentation of the underlying pathophysiological mechanisms of ischaemia by intracoronary Doppler and pressure measurements

Only a few cases of a single coronary ostium and retroaortic course of the coronary artery have been described. Almost all cases reported so far had additional coronary artery or valvar disease. However, myocardial ischaemia may be caused by the coronary malformation alone. A 40 year old woman with severe myocardial ischaemia in the absence of clinically relevant coronary atherosclerosis is described. To clarify the origin and mechanisms of ischaemia, intracoronary Doppler, pressure and ultrasound studies were performed using microtransducers. In its outer portion along the course behind the ascending aorta, coronary blood flow velocities were increased, there was an external elliptical compression, and distal coronary flow reserve was reduced. Furthermore, an overshoot in diastolic pressure above aortic pressure was detectable within this portion. Dobutamine stimulation exaggerated the observed intracoronary haemodynamics and induced myocardial ischaemia. The intracoronary diagnostic procedures performed were helpful in clarifying the pathophysiological mechanisms of functional coronary obstruction and ischaemia in this malformation. Bypass surgery was successfully performed with symptomatic improvement.

Keywords: coronary anomaly;  Doppler;  intravascular ultrasound;  single coronary ostium;  congenital disorders     

Ten year follow up of patients referred for coronary artery bypass grafting from a single district general hospital

Objective—To determine the status of patients 10 years after referral for coronary artery bypass graft (CABG) surgery.
Design—Retrospective analysis of case notes from all patients referred between 1 April 1981 and 31 March 1985. Full information gathered from hospital notes, GP records, and Registrar General for Scotland.
Setting—District General Hospital, West Lothian, Scotland.
Patients—102 patients referred for CABG during study period. Cardiac surgery was undertaken in Brompton Hospital, London, Royal Infirmary, Edinburgh, and Western Infirmary, Glasgow.
Results—At 10 years after operation 32 patients had died (27 cardiac, five non-cardiac causes). Full data were not available for five patients. Of the 65 remaining patients 24 had no angina, 13 had had a repeat procedure (CABG or angioplasty), and 28 had angina.
Conclusions—Long term benefits of CABG surgery is disappointing. Further steps are required to reduce progression of disease in this population.

Keywords: coronary artery bypass surgery;  repeat procedure;  survival;  audit     

Marfan syndrome in children and adolescents: an adjusted nomogram for screening aortic root dilatation

Objective—To construct an adjusted nomogram for the echocardiographic screening of aortic root diameter in children with possible Marfan disease.
Design—In 91 children (42 boys, 49 girls, age range 3.2 to 18.4 years) undergoing Marfan screening from 1983 until 1996, the diagnosis Marfan syndrome and any other aortic pathology was definitely ruled out. These served as a control population to set appropriate reference standards.
Results—Compared with a standard Dutch reference population, body surface area of the control subjects (mean (SD)) was above the 50th centile (boys 0.09 (0.20) m², range −0.28 to 0.69 m²; girls 0.09 (0.17) m², range −0.17 to 0.69 m²). Echocardiographically determined aortic root diameter and body surface area showed a linear relation and a greater variability of aortic root diameter in these relatively tall subjects (n = 91, R² = 0.62) than in the standard nomogram (n = 56, R² = 0.93). In 24% of cases (n = 22), the aortic root exceeded the upper limit of normal in the standard nomogram, by 2.2 (2.0) mm. An adjusted nomogram was constructed with a higher upper limit.
Conclusions—A Marfan screening population differs from the unselected population in body surface area and aortic root size variability. An adjusted nomogram should therefore be used to detect a truly enlarged aortic root.

Keywords: Marfan syndrome;  aorta;  nomogram;  children     

Tyrosine phosphorylation of platelet derived growth factor β receptors in coronary artery lesions: implications for vascular remodelling after directional coronary atherectomy and unstable angina pectoris

Background—Growth factors such as platelet derived growth factor (PDGF) have been postulated to be important mediators of neointimal proliferation observed in atherosclerotic plaques and restenotic lesions following coronary interventions. Binding of PDGF to its receptor results in intrinsic receptor tyrosine kinase activation and subsequent cellular migration, proliferation, and vascular contraction.
Aims—To investigate whether the concentration of PDGF β receptor tyrosine phosphorylation obtained from directional coronary atherectomy (DCA) samples correlate with atherosclerotic plaque burden, the ability of diseased vessels to remodel, coronary risk factors, and clinical events.
Methods—DCA samples from 59 patients and 15 non-atherosclerotic left internal thoracic arteries (LITA) were analysed for PDGF β receptor tyrosine phosphorylation content by receptor immunoprecipitation and antiphosphotyrosine western blot. The amount of PDGF β receptor phosphorylation was analysed in relation to angiographic follow up data and clinical variables.
Results—PDGF β receptor tyrosine phosphorylation in the 59 DCA samples was greater than in the 15 non-atherosclerotic LITA (mean (SD) 0.84 (0.67) v 0.17 (0.08) over a control standard, p < 0.0001). As evaluated by stepwise regression analysis, incorporation of both PDGF β receptor tyrosine phosphorylation and immediate gain correlated strongly (adjusted r² = 0.579) with late loss, although PDGF β receptor tyramine phosphorylation alone correlated poorly with late loss. Multivariate regression analysis of coronary risk factors and clinical events revealed unstable angina as the most significant correlate of PDGF β receptor tyrosine phosphorylation (F value 20.009, p < 0.0001).
Conclusions—PDGF β receptor tyrosine phosphorylation in atherosclerotic lesions is increased compared with non-atherosclerotic arterial tissues. The association of PDGF β receptor tyrosine phosphorylation with immediate gain strongly correlates with vascular remodelling. PDGF β receptor tyrosine phosphorylation correlates with unstable angina pectoris.

Keywords: PDGF receptors;  atherosclerosis;  directional coronary atherectomy;  restenosis     

Prevalence of factor V Leiden (APCR) and other inherited thrombophilias in young patients with myocardial infarction and normal coronary arteries

Objective—To investigate the role of activated protein C resistance (APCR, factor V Leiden) in coronary artery thrombosis.
Methods—The prevalence of APCR and of congenital deficiencies of antithrombin III, protein C, protein S, plasminogen, and factor XII was investigated in adult patients under 45 years of age with acute myocardial infarction. The results were compared with those of a group of 53 age and sex matched control subjects.
Results—Among 75 patients under the age of 45 years who were admitted from November 1994 to April 1996 for acute myocardial infarction, 22 (29.3%) had normal coronary arteriography (group I) and 53 (70.7%) had significant coronary artery disease (group II). Inherited thrombophilia was more often found in group I (4/22, 18.2%) than in group II (4/53, 7.5%) but the difference was not significant (F test: p = 0.22). The prevalence of APCR was 9.1% (2/22) in group I, 3.8% (2/53) in group 2 (p = 0.57), and 3.8% (2/53) in the normal control group (p = 0.57).
Conclusions—The prevalence of congenital thrombophilias, including APCR, does not seem to be increased in young patients with myocardial infarction and normal coronary angiograms, compared with young patients with coronary atherosclerosis and with normal control subjects. However, the statistical power of the study is too low to detect a significant difference and these results are published to allow a meta-analysis of this problem in the future.

Keywords: myocardial infarction; factor V Leiden; coagulation factors; inherited thrombophilia     

Percutaneous treatment of stenosed major aortopulmonary collaterals with balloon dilatation and stenting: what can be achieved?

Background—The natural history of major aortopulmonary collateral arteries (MAPCAs) in patients with pulmonary atresia and ventricular septal defect (PA-VSD) is frequently complicated by progressive stenosis, leading to pulmonary hypoperfusion and debilitating hypoxaemia.
Objective—To evaluate balloon dilatation and stenting for relief of stenoses and improvement of pulmonary flow in patients with PA-VSD.
Design—Retrospective analysis of all patients where dilatation of MAPCA stenoses was attempted.
Patients—Twelve patients with stenotic MAPCAs.
Interventions—Dilatation was attempted in 25 stenoses. Vessels were stented if elastic recoil was noticed (n = 3), in the presence of long segment stenosis (n = 4) or marked tortuosity (n = 1).
Main outcome measures—Diameter of stenoses before and after dilatation as well as arterial oxygen saturation data. Patients proceeding to surgical therapy.
Results—Two stenosed MAPCAs could not be crossed by a catheter. Four lesions were non-dilatable despite the use of high inflation pressures (18 atm). Six stenoses could be completely dilatated using angioplasty only; in five, only partial dilatation was obtained; eight stenoses needed stenting. In the group with partial expansion the mean (SD) diameter increased from 1.7 (0.8) to 3.5 (1.7) mm (p < 0.05); where full dilatation was achieved it increased from 2.1 (0.8) to 4.8 (1.9) mm (p < 0.05); and in the stented group it increased from 2.3 (0.9) to 5.0 (2.5) mm (p < 0.01). Percutaneous arterial oxygen saturation increased from 75(8)% to 82(8)% (p < 0.001). No complications were experienced during the procedures. Repeat dilatation was attempted in six stenoses, but only two procedures were successful. There were two episodes of vasospasm and in one an aneurysm had developed after redilatation. Two patients proceeded to outflow plasty and two subsequently had a unifocalisation procedure.
Conclusions—Pulmonary blood flow can be improved using balloon angioplasty or stents in patients with stenotic MAPCA; however, 17% of the lesions were not dilatable. Procedures are generally safe, but carry a small risk of vasospasm, dissection, occlusion or aneurysm formation.

Keywords: major aortopulmonary collateral arteries; pulmonary atresia and ventricular septal defect; angioplasty; stenting; interventional cardiology