A recent study published in JACC evaluated the two year results of FFR guided PCI (percutaneous coronary intervention). Pijls NHJ et al reported the two year follow up of the FAME (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) study which had shown that FFR improves the outcome of PCI at one year. The study involved over one thousand patients with multi vessel coronary artery disease randomized to PCI with either angiographic guidance alone or with FFR in addition. In the angiography alone guided group, the decision for stent was depending on the visual appearance of the lesion. In the FFR guided group, stents were deployed only for the lesions which showed and FFR of 0.80 or less. The other lesions were left on medical management. Naturally the FFR guided group received lesser number of stents. They had lower rates of mortality or myocardial infacrtion. PCI or coronary artery bypass surgery rates were also lower, though not statistically significant. The lesions deferred on basis of FFR had only a 0.2% myocardial infarction rate and 3.2% revascularization rate. A downside of the study was that it had included lesions of 50 to 79% stenosis also. But the author justify their decision mentioning that 35% of these lesions were hemodynamically significant and leaving them untreated based on angiographic appearance alone would not have been ideal. Another potential draw back of the data is that theoretically the lesions left alone based on FFR can also progress beyond the study period of two years and present later with significant stenosis.

But there was higher risk of stroke during the periprocedural period in the stenting group and higher risk of myocardial infarction with endarterectomy. After that period, the events were similar in both groups.

Symptoms considered for inclusion in the symptomatic group were transient ischemic attack, amaurosis fugax or minor non-disabling stroe in the carotid territory within 6 months before randomization. Stenosis required for inclusion was 50% or more angiographic stenosis or 70% or more stenosis on ultrasonography or 70% or more stenosis on CT or MR angiography when ultrasonic stenois was reported between 50 to 69%. The eligibility criteria was different in the asymptomatic group, requiring 60% or more angiographic stenosis, 70% or more ultasonic stenosis or 80% or more stenosis on CT or MR angiographic stenosis when ultrasonic stenosis was 50 to 69%.

Distal protection devices were used for stenting whenever feasible. Aspirin and clopidogrel pretreatment was given prior to stenting and continued afer procedure. Loading dose of aspirin and clopidogrel were given when stenting occurred within 48 hours of randomization. Endarterectomy patients were pretreated with aspirin for at least 48 hours and continued after the procedure. Alternatives for aspirin were ticlopidine, clopidogrel or a combination of aspirin with extended relears dipyridamole.

The authors claim that the rate of stroke or death for the symptomatic patients with carotid stenting in their study was lower than the corresponding rates in the SPACE trial, EVA-3S trial and ICSS. The rate of stroke or death for symptomatic patients with carotid endarterectomy was also lwoer than in SPACE trial and was similar to that in EVA-3S and ICSSS. The rate of stroke or death in the carotid artery stenting group was similar to that in Asymptomatic Carotid Atherosclerosis Study (ACAS) and lower than in Asymptomatic Carotid Surgery Trial (ACST). Corresponding rates were lower for carotid endarterectomy group as well.

Another study published in the same issue of the journal also made similar conclusions.

Myocardium is perfused through a coronary vein in a retrograde fashion in another procedure known as PICVA (Percutaneous In situ Coronary Venous Arterialization). In that procedure, a fistula is created from the artery proximal to the obstruction to the coronary vein using a self expanding connector. The proximal vein is plugged off to prevent steal of blood into the coronary sinus. This technique will force retroperfusion of the myocardium through the coronary vein. The procedure has been be done between proximal left anterior descending coronary artery and the anterior interventricular vein to perfuse the anterior wall in a case of diffuse left anterior descending artery disease with no other options http://circ.ahajournals.org/cgi/content/full/103/21/2539.

Heparin and intracoronary nitroglycerine are given before the guide wire is inserted after the coronary cannulation with a guide catheter. The IVUS catheter is then introduced over the guide wire. Images are continuously recorded by the system for later review and analysis.

Measurements in IVUS

Measurements in IVUS include the measurement of lumen, plaque, calcium, remodeling, stent, length and volumetric measurements.

Plaque morphology

Plaque morphology can be assessed in terms of its geometry and echogenicity. In the geometry, the size of the plaque, its relationship to luminal stenosis, arterial remodeling and eccentricity can be evaluated. Echogenicity could be regarding echolucent and echodense as well as calcified plaques. Thrombus and intimal hyperplasia can be noted. A vulnerable plaque and a plaque with ulceration or rupture can also be found.

Important applications of IVUS

Assessment of an angiographically indeterminate lesion, especially that of the left main coronary artery, is an important reason for an IVUS study. It can also guide guidance for stenting in terms of assessment of stent apposition and good expansion. IVUS can also delineate intramural hematoma and dissection.

Artifacts in IVUS

Artifacts are possible in an IVUS study due to guide wire artifacts, ring down artifacts, non-uniform rotational distortion, slow flow, coronary pulsation and motion, catheter obliquity and eccentricity and calcium shadow.

Potential complications of an IVUS study

Major complications are rare and could include dissection or vessel occlusion. But these major complications occur usually during interventions rather than diagnostic IVUS evaluations. Vasospasms are usually transient and respond to intracoronary nitroglycerine. Transient ischemia may occur while negotiating tight stenosis or small vessels. IVUS should be performed only by operators with significant experience in diagnostic and interventional procedures in the coronaries.

When to suspect congenital heart disease in a new born?

New born with difficulty in breathing, cyanosis, feeding difficulty, undue lethargy or undue irritability and insolable cry after feeding (suspect ALCAPA – anomalous origin of left coronary artery from pulmonary artery) are the situations in which congenital heart disease is suspected in a new born.

Physical examination

Physical examination is often difficult in a sick infant, but should include the assessment of pulse, respiration, colour, tone, activity, cry and murmurs. Occasionally a bounding pulse with heart failure and a large heart, but a normal echocardiogram (except for chamber dilatations), may be due the the vein of Galen aneurysm producing an arteriovenous shunting. Many infants may be branded as cardiomyopathy if a careful examination of femoral pulse is not performed to identify coarctation of aorta. Respiratory distress with increased effort as evidenced by a tracheal tug mandates ventilation. Pallor may be noted in heart failure and cyanosis in hypoxemia. Hypotonia with severe decrease in activity suggests a severe cardiac lesion. Please note that the absence of a murmur does not rule out severe congenital heart disease.

Role of X-ray chest

The x-ray chest is useful to know the state of the pulmonary blood flow, whether it is oligemic or plethoric. It is also useful for ruling out lung pathology and identifying the situs of the heart and the viscera. Oligemic lung field with a prominent main pulmonary artery segment would suggest tetralogy of Pulmonary artery with absent pulmonary valve. A large heart in a newborn should make us suspect Ebsteins anomaly of the tricuspid valve or a critical pulmonary stenosis with heart failure. Agenesis of the lung, collapse of the lung, eventration of the diaphragm and diaphragmatic hernia may be seen on the chest x-ray.

Hyperoxia test

Oxygen may be given with a hood or mask for 1 minutes, evaluating the blood before and after 100% oxygen. Saturation, PO2 and PCO2 are checked before and after the hyperoxia test. The test is useful in differentiating cyanotic congenital heart disease from lung disease.

Concerns against a hyperoxia test:

There is some concern over the induction of an irreversible ductal spasm in a ductus dependent new born, though it is extremely uncommon. Ductal spasm can also occur even without oxygen administration. Ideally PGE1 should be available to tackle duct spasm.

Pulse oximetry in the new born

Pulsoximetry should be done in all four limbs as desaturation may be there only in the lower limbs in certain situations. Obtaining a good pulsoximetry may not be easy in a sick infant. The limbs should be warm to avoid errors. The visual and auditory signals associated with pulsoximetry should be good. A good plethysmograph ensures accuracy of the technique.

Role of ECG

Arrhythmias causing tachycardiomyopathy may be occasionally identified in a new born with heart failure. New born hearts are extremely prone for heart failure with prolonged tachyarrhythmias. Big Q waves in lateral leads could suggest ALCAPA.

Role of echocardiography

Echocardiography is the most important diagnostic tool in a new born with suspected congenital heart disease. A systematic and segmental approach is essential to avoid missing important lesions. The coronaries should be specifically looked for. Optimum machine which is dedicated to echocardiography with a good neonatal probe is ideal. There is no need to emphasise the need for trained personnel. If a coarctation is not seen from the suprasternal or parasternal views, an epigastric view might demonstrate a coarctation of the abominal aorta. Other lesions which can be easily missed are infra diaphragmatic TAPVC (total anomalous pulmonary venous connection) and coarctation in the presence of a PDA (patent ductus arteriosus). Repeat echoes and second opinions are needed in difficult cases.

Role of computerised tomography (CT)

CT is useful in the differentiation of coarctation of aorta from aortic arch interruptions. Pulmonary venous drainage in heterotaxy may also be better seen on CT.

Cardiac emergencies in the newborn

They may present with severe hypoxia, severe heart failure or cardiovascular collapse. This could be because the anatomical lesions are critical or because of associated complications like pneumonia, gastroenteritis or anemia. These infants are very sick and need rapid triage and management.

Treatment of emergencies in infants with trans catheter techniques

Treatment of emergencies require a good team work of experts, good imaging and a large inventory of hardware with preferably no constraints of cath lab time or money. The expert team is composed of intensivists, anaesthetists, nurses, technicians, cardiac surgeons and the interventional cardiologists. New born emergencies are very sick with associated hypoxia, acidosis, dehydration, hypoglycemia and electrolyte imbalance. They have poor ventricular function and a low safety margin. Failed procedure in this situation would mean a higher mortality than not attempting the procedure at all.

The protocol is to stabilise initially in a new born intensive care unit (NICU) and then optimally time the intervention – not too early or too late. Attention has to be made to baseline parameters, airway and ventilation, intravenous access, blood investigations, hydration, correction of anemia, acidosis and electrolyte imbalance. Echocardiography and screening for clotting abnormalities are needed.

Once the vascular access for intervention is obtained, it is almost like half the work done. Care with contrast injection is needed to avoid cardiac and renal dysfunction in the sick neonate.

Interventional procedures in the newborn

Dilatation of valves – balloon aortic valvuloplasty (BPV), balloon pulmonary valvuloplasty

Perforation of valves – pulmonary valve in pulmonary atresia

Dilatation of vessels – coarctation of aorta

Maintaining ductal patency – stenting of the duct

Closure of PDA with coil or device

Balloon atrial septostomy

Embolisation of accessory channels as vein of Galen aneurysm or in Scimitar syndrome

Balloon atrial septostomy may even be done in the neonatal ICU in very sick infants under echo guidance. Fetal diagnosis may enable tackling of the lesion on day 1 itslef. Neonatal BPV can be done with coronary guide wires and balloons. Perforation of the atretic valve in pulmonary atresia may be done with the hard end of a guide wire. The perforation is crossed with a coronary wire and serially dilated with coronary balloons. Sometimes the perforation is also stented, though it will produce significant pulmonary regurgitation. Critical aortic stenosis can also be dilated similarly. Severe coarctation can also be dilated, though it may be a palliative procedure as a bridge to surgery. Dilatation with or without stenting for an occluded Blalock Taussig shunt is another trans catheter procedure. Recurrence is likely and needs a more definitive treatment.

Hybrid procedures in the new born

Hybrid procedures can be done either in the operating room or in hybrid suites. In closing a muscular VSD in a sick neonate not suitable for cardiopulmonary bypass, after sternotomy, the right ventricle is punctured and a guide wire is passed across the VSD. The sheath is then threaded over it followed by device delivery.