574 Br HeartJ 1993;69:574-577 TECHNIQUE Br Heart J: first published as 10.1136/hrt.70.6.574 on 1 December 1993. Downloaded from Intractable chest pain in cardiomyopathy: treatment by a novel technique of cardiac cryodenervation with quantitative immunohistochemical assessment of success J AR Gaer, L Gordon, J Wharton, J M Polak, K M Taylor, W McKenna, D J Parker Abstract she described episodes of chest pain, usually A novel method of cardiac denervation on exertion but also at rest and at night. The by cryoablation has been developed ex- pain occurred up to 10 times daily and her perimentally. The technique uses liquid exercise tolerance had deteriorated from four nitrogen delivered under pressure to miles to 200 yards. Although she denied ablate the principal sources of cardiac paroxysmal nocturnal dyspnoea, she slept innervation-namely, the adventitia sur- with three pillows. Her medication at this rounding the aorta, pulmonary arteries, time consisted of sotalol (80 mg twice daily) and veins. The technique has been veri- and verapamil (240 mg twice daily). She had fied experimentally both in vivo by four children (aged 6, 8, 10, and 11 years) all physiological means and in vitro by of whom were healthy. She was unaware of a quantitative immunohistochemistry and family history of hypertrophic cardiomyopa- the measurement of myocardial nor- thy, although two members of her family had adrenaline concentrations. A 35 year old died suddenly in middle age. On admission a woman presented with intractable pre- soft pansystolic murmur and considerable cordial pain, normal epicardial coronary obesity were noted. arteries, and hypertrophic cardiomyo- pathy. Her symptoms were refractory to INVESTIGATIONS maximal medical treatment and she was Haematological and biochemical variables thought to be unsuitable for either con- were normal. A resting 12 lead electrocardio- http://heart.bmj.com/ ventional myocardial revascularisation, gram showed T wave inversion in leads I, autotransplantation, or allografting with aVL, and V4-V6, and her chest x-ray film on the concomitant risk of transplant coro- admission was normal. A transthoracic nary artery disease. She therefore under- echocardiogram showed considerable concen- went cardiac denervation by the method tric hypertrophy, good posterior movement, developed in the laboratory. There was and a small end systolic volume. Left heart quantitative immunohistochemical evi- catheterisation showed normal coronary Royal Postgraduate dence of extrinsic cardiac denervation arteries with no left ventricular outflow tract on September 24, 2021 by guest. Protected copyright. Medical School, Hammersnith associated with a considerable improve- gradient and a left ventricular end diastolic Hospital, L6ndon ment in her symptoms. This improve- pressure of 24 mm Hg (table 1). The patient Department of ment persisted during a follow up period managed five minutes of a Bruce protocol Cardiothoracic Surgery of over 16 months. during which time her blood pressure fell JAR Gaer from 120/80 mm Hg to 100/50 mm Hg. K M Taylor (Br HeartJ 1993;70:574-577) There were no significant ST-T wave Department of changes. Her VO2max was 17-0 ml/min/kg Histochemistry a of 1-03. Thallium L Gordon with respiratory quotient J Wharton Case report exercise tests showed increased apical uptake J M Polak A 35 year old woman presented initially in of isotope with reverse redistribution on St George's Hospital, 1985 with a two week history of cough, delayed scanning suggestive of reversible London anorexia, nausea, and lethargy. An apical sys- ischaemia. Oesophageal manometry and a Department of Cardiology tolic murmur was noted and echocardiogra- W McKenna phy suggested hypertrophic cardiomyopathy. Department of She was then lost to follow up but returned in Table 1 Preoperative and postoperative left and right Cardiothoracic 1989 with a two year history of chest pain. heart catheteisation pressures (mm Hg) Surgery D J Parker This had been diagnosed as angina secondary Preoperative Postoperative to hypertrophic cardiomyopathy. Treatment Correspondence to: PA (mean) 30/18 (20) 20/6 (8) J AR Gaer, Department of with diltiazem, verapamil, and ,B blockers did PAW 17 6 Cardiothoracic Surgery, not improve her symptoms. She was fitted LV systolic 120 120 Rtyal Postgraduate Medical Aorta (mean) 120/70 (90) 120/75 (95) School, Hammersmith with an AV sequential pacemaker because of LVEDP 24 12 Hospital, Du Cane Road, her worsening exercise tolerance, but this too London W12 ONN. PA, pulmonary artery; PAW, pulmonary artery wedge; LV, Accepted for publication was of no benefit. left ventricular; LVEDP, left ventricular and diastolic 15 June 1993 She was first seen by us in June 1990 when pressure. Intractable chestpain in cardiomyopathy: treatment by cardiac cryodenervatiow with quantitative immunohistochemical assessment ofsuccess 575 Bernstein's test were unequivocally normal. in her symptoms, having had no significant Coronary flow reserve was assessed with chest pain since the operation. Associated intra-arterial adenosine. This showed an with this, however, she reported a worsening increase in coronary flow of 10% compared of her dyspnoea. Left and right heart with a predicted increase of 300%-400%. On catheterisation was repeated about six months Br Heart J: first published as 10.1136/hrt.70.6.574 on 1 December 1993. Downloaded from the basis of this information the presumptive after the operation (table 1). It is of interest diagnosis was one of a hypertrophic cardio- that, despite her increased breathlessness, myopathy with angina due to an abnormality both her pulmonary capillary wedge and left of vasomotor control. ventricular end diastolic pressures had fallen considerably. Her VO2max was 14 ml/min/kg, MANAGEMENT there were no ST-T wave changes and her A variety of medical manoeuvres were blood pressure response was normal. attempted, including manipulation of the AV Thallium scanning showed no defects but delay on her pacemaker (with exercise tests radionuclide assessment of systolic function before and after), high dose diltiazem treat- showed a fall in ejection fraction from 71% to ment (720 mg/day), and medium dose dilti- 55%. azem treatment with added captopril and dipyridamole. Transcutaneous nerve stimula- IMMUNOHISTOCHEMICAL ANALYSIS tion with a temporary dorsal column nerve Biopsy specimens were taken from the right stimulator at the level of the sixth cervical ventricle at the time of surgery and at 11 and vertebra was attempted at frequencies of 39 days postoperatively. Also the right atrial stimulation ranging from 35-120 Hz over a appendage was removed before denervation. period of one week. None of these measures These specimens were subjected to immuno- relieved the symptoms. Ultimately, the histochemical analysis with the techniques patient consented to undergo complete that we have described in detail elsewhere.3 cardiac denervation by the technique Briefly, biopsy specimens were fixed imme- described here. diately in a modified Bouin's solution4 for one to three hours and an indirect immuno- OPERATIVE TECHNIQUE fluorescence technique was used to localise The heart was exposed through a median the general neural marker protein PGP 9.5 sternotomy. The left ventricle seemed moder- and the regulatory peptide neuropeptide Y ately hypertrophied overall, but the apex was (NPY). After staining with established anti- virtually non-contractile. Although the tech- sera to PGP 9-5 and NPY, the slides were nique is performed in animals without it, we subjected to quantitative immunohisto- elected to use cardiopulmonary bypass to chemical analysis with a Kontron VIDAS carry out the extensive disection and manipu- (Kontron Electronik Ltd, Watford) image lation of the heart that was required. Bypass processing system, interfaced to an Olympus was established between bicaval venous and AH-2 microscope through a low light video ascending aortic cannulation. The right atrial camera. Measurements of total field area http://heart.bmj.com/ appendage and free wall of the right ventricle (myocardium) and segmented area (immuno- were biopsied before any dissection was fluorescent nerves) were obtained for each started. These biopsy specimens were subse- field and the percentage fluorescent area quently subjected to quantitative immuno- derived for each immunostained section. All histochemical analysis. The aorta, pulmonary fields were measured for each preparation artery, and superior and inferior venae cavae and comparative measurements were made of were fully mobilised. The adventitia was myocardial innervation alone. stripped from 5 cm of the ascending aorta. on September 24, 2021 by guest. Protected copyright. The interatrial groove was mobiised to give STATISTICS access to the transverse sinus and allow All data are presented as the mean and 95% mobilisation of the pulmonary veins. Lengths confidence interval (95% CI). The propor- of polyvinyl chloride (PVC) tubing were tion of immunoreactive nerve subtypes in threaded arouind the pulmonary veins and the innervated and denervated myocardium were ascending aorta in an identical manner to that compared by analysis of variance of log trans- described inr animal models.12 These were formed data. A p value <0 05 was considered connected in turn to a modified Dewar flask to be significant. containing liquid nitrogen. Compressed air was pumped into the Dewar flask to deliver RESULTS OF IMMUNOHISTOCHEMICAL liquid nitrogen under pressure into the PVC ANALYSIS tubing. This process was carried