P392 A MULTIMODALITY IMAGING DIAGNOSIS OF A CHALLENGING CASE OF CONCOMITANT GROUP 1 PULMONARY HYPERTENSION AND PARADOXICALLY LOW–FLOW, LOW–GRADIENT AORTIC STENOSIS

 

A 76 year old woman was admitted to our hospital for self–limiting dyspnoea (NYHA class III) in oxygen dependence and frequent lipothymia following Valsalva manoeuvres. She was previously admitted to a Spoke Centre for heart failure (HF) with preserved ejection fraction (EF) and a new diagnosis of “pre–capillary pulmonary hypertension (PH)”. Despite a diagnosis of PH of unclear aetiology, she was started on macitentan without being reassessed for functional capacity due to Covid emergency; because of worsening symptoms, she was admitted to our Hub Centre. Resting ECG showed right axis deviation, right ventricle (RV) hypertrophy, first–degree atrioventricular block and right bundle branch block. Transthoracic echocardiography (TTE) showed reduced left ventricular (LV) volume with preserved EF (diastolic volume= 37 ml, EF = 88%), severe right atrial and RV dilation with flattening of the interventricular septum, estimated pulmonary artery systolic pressure (PASP) of 124 mmHg, and moderate calcific aortic stenosis (peak aortic velocity 3.3 m/s, mean gradient 25 mmHg, valve area 1.1 cm2). Right and left heart catheterization showed severe pre–capillary PH (mean pulmonary pressure 60 mmHg, mean wedge 11 mmHg, pulmonary vascular resistance 14.41 WU), a severe aortic valve stenosis (aortic valve area 0.68 cmq and peak–to–peak gradient 25 mmHg, slight reduction of cardiac index 2.04 l/min/mq) and no significant coronary artery disease. The degree of aortic stenosis was considered as moderate–severe by integrating data of transesophageal echocardiography (planimetric area 1cm2) and assessment of calcium score (1615 Agatson units). Pneumological causes, chronic thromboembolic PH, rheumatologic diseases, HIV infection, paraneoplastic origin and veno–occlusive disease were all ruled out as potential PH causes and a diagnosis of Idiopathic pulmonary arterial hypertension (IPAH) was finally made. The Heart Team established the best therapeutic option was a transcatheter aortic valve replacement (TAVI) allowing better haemodynamic tolerability of PH therapy. The patient underwent TAVI and was started on PH therapy; a complete atrio–ventricular block developed after the procedure, requiring permanent pacemaker (PM) implantation. Unfortunately, few days later, the patient died following pacemaker’s lead dislocation.

Conclusion

PH has a diverse aetiology, and prognosis is generally poor, especially in patients with severe comorbidities.

P430 TUMORAL THROMBOTIC MICROANGIOPATHY: A RARE CAUSE OF ACUTE PULMONARY HYPERTENSION

Introduction

Among the causes of acute pulmonary hypertension, the occlusion of the little pulmonary vessels caused by tumoral microemboli, even from an unknown neoplasm, is an infrequent condition with a very poor prognosis.

Clinical Case

A 55–years old woman with no relevant past medical history presented to the Emergency Department with dyspnea at rest, desaturation, palpitations and a brief episode of chest pain, after several days of fatigue and exertional dyspnea. ECG showed sinus tachycardia and signs of right ventricle pressure overload with inverted T waves in V3–V4 and in the inferior leads (Fig. 1). On laboratory tests there were high D–dimer values and a slightly elevated TnI. Blood gas analysis showed hypoxemic hypocapnic respirstory alkalosis. An Echocardiogram revealed severe dilatation and dysfunction of the right ventricle and signs of high probability of pulmonary hypertension (Fig. 2). Pulmonary CT scan ruled out embolism and showed irregular thickening of the interstitium and mediastinal lymphoadenopathy. Then, a rapid clinical deterioration happened, refractory to inotropes infusion and larger volumes of oxygen. The programmed diagnostic pathway cannot be pursued. On day 4, there was respiratory distress and pulseless electrical activity cardiac arrest during endotracheal intubation. ECMO mechanical support was positioned but on day 7 the patient died. Autopsy, made to discover the cause of pulmonary hypertension, revealed the presence of a colonic invasive adenocarcinoma with micropapillary pattern and thoracic and pelvic lymph–nodal metastases. Microscopic evaluation of the lungs showed a widespread neoplastic vascular invasion with microthromboemboli (Fig. 3).

Discussion

Tumoral thrombotic microangiopathy is a cause of pulmonary hypertension of multifactorial origin and should be suspected in cases of pulmonary hypertension without pulmonary embolism or interstitial lung disease. The rarity of this condition and the absence of an oncological medical history make difficult the diagnostic hypothesis. Besides, the lacking of an effective therapy makes the prognosis poor.

Rare cardiomyopathies: diagnostic features

Cardiomyopathies (CM) are an important and heterogeneous group of diseases affecting the myocardium. They can induce mechanical and/or electrical disorders and are due to a variety of causes, they frequently are genetic. However, since their high number and their clinical complexity, the identification is still a challenge. Echocardiography is a very useful tool in the assessment of CM. In this review we aim to define the typical clinical features and to discuss the main diagnostic tool, above all echocardiography that can help physicians in the correct assessment of CM.

Decisional trees in renal transplant follow-up

INTRODUCTION

The predictive potentialities of application of data mining algorithms to medical research are well known. In this article, we have applied to a transplant population classification trees to build predictive models of graft failure, evaluating the interactions between body mass index (BMI) and other risk factors. The decision trees have been widely used to represent classification rules in a population by a hierarchical sequential structure.

PATIENTS AND METHODS

We retrospectively studied 194 renal transplant patients with 5 years of follow-up (128 males, 66 females, mean age at time of transplant of 43.9 +/- 12.5 years). Exclusion criteria were: age < 18 years, multiorgan transplant, and retransplant. The BMI was calculated at the time of transplantation. In the classification algorithm, we considered the following parameters: age, sex, time on dialysis, donor type, donor age, HLA mismatches, delayed graft function (DGF), acute rejection episode (ARE), and chronic allograft nephropathy (CAN). The primary endpoint was graft loss within 5-years follow-up.

RESULTS

The classification algorithm produced a decision tree that allowed us to evaluate the interactions between ARE, DGF, CAN, and BMI on graft outcomes, producing a validation set with 88.2% sensitivity and 73.8% specificity. Our model was able to highlight that subjects at risk of graft loss experienced one or more events of ARE, developed DGF and CAN, or has a BMI > 24.8 kg/m(2) and CAN.

CONCLUSIONS

The use of decision trees in clinical practice may be a suitable alternative to the traditional statistical methods, since it may allow one to analyze interactions between various risk factors beyond the previous knowledge.

Prediction of chronic allograft nephropathy using classification trees

INTRODUCTION

For its intrinsic potential to mine causal relations, machine learning techniques are useful to identify new risk indicators. In this work, we have shown two classification trees to predict chronic allograft nephropathy (CAN), through an evaluation of routine blood and urine tests.

METHODS

We retrospectively analyzed 80 renal transplant patients with 60-month follow-up (mean = 55.20 +/- 12.74) including 52 males and 28 females of overall average age of 41.65 +/- 12.52 years. The primary endpoint was biopsy-proven CAN within 5 years from transplantation (n = 16). Exclusion criteria were multiorgan transplantations, patients aged less than 18 years, graft failure, or patient death in the first 6 months posttransplantation. Classification trees based on the C 4.8 algorithm were used to predict CAN development starting from patient features at transplantation and biochemical test at 6-month follow-up. Model performance was showed as sensitivity (S), false-positive rate (FPR), and area under the receiver operating characteristic curve (AUC).

RESULTS

The two class of patients (no CAN versus CAN) showed significant differences in serum creatinine, estimated Glomerular Filtration Rate with Modification of Diet in Renal Disease study formula (MDRD), serum hemoglobin, hematocrit, blood urea nitrogen, and 24-hour urine protein excretion. Among the 23 evaluated variables, the first model selected six predictors of CAN, showing S = 62.5%, TFP = 7.2%, and AUC = 0.847 (confidence interval [CI] 0.749-0.945). The second model selected four variables, showing S = 81.3%, TFP = 25%, and AUC = 0.824 (CI 0.713-0.934).

CONCLUSIONS

Identification models have predicted the onset of multifactorial, complex pathology, like CAN. The use of classification trees represent a valid alternative to traditional statistical models, especially for the evaluation of interactions of risk factors.

Angiotensin antagonists and fish oil for treating IgA nephropathy

In IgA nephropathy (IgAN), ACE inhibitors (ACE-I) and angiotensin receptor blockers (ARB) are beneficial against hypertension, and their anti-proteinuric effect has been clearly demonstrated. However, sub-analyses of IgAN patients enrolled in large studies failed to prove a benefit against progression to renal failure. The European Community Biomed Concerted Action - a placebo-controlled randomized controlled trial begun in 1995 - in children and adults (9-35 years old) with proteinuria > 1 < 3.5 g/day/1.73 m(2) and normal or moderately reduced renal function proved the significant benefit of ACE-I on progression of kidney disease. The combination of ACE-I and ARB in proteinuric normotensive IgAN patients showed greater antiproteinuric effect and the COOPERATE trial also reported a superior effect of combination therapy in protecting against renal function deterioration. Treating IgAN with fish oil has a good rationale for renal inflammation as well as for prevention of cardiovascular morbidity. However, the published reports gave conflicting conclusions and also very recent data did not show significant benefits. In conclusion, ACE-I and ARB have a definite role in treating IgAN, particularly the hypertensive and proteinuric forms. These patients should be treated to target BP to <130/70 mm Hg and proteinuria <0.5 g/day.

Characterization of the Na+/H+ exchanger in human epidermoid carcinoma A431 vesicles

A previous report from this laboratory (Rothenberg et al., 1983a) demonstrated the presence of an Na+/H+ exchanger in human epidermoid carcinoma A431 cells. We now characterize surface-derived membrane vesicles from this cell line which contain a functional Na+/H+ exchanger. The Na+/H+ exchanger in A431 vesicles shares a number of characteristics in common with previously described Na+/H+ exchangers including the following: (1) Na+ uptake is stimulated by an outward-directed pH gradient and inhibited by an inward-directed pH gradient. (2) Na+ uptake is inhibited by amiloride and its analogs and their relative effectiveness is similar in vesicles and A431 cells. (3) The Na+/H+ exchanger uses Na+ or Li+ as a substrate but not K+ or Cs+. (4) H+ efflux is stimulated by an inward-directed Na+ gradient and inhibited by the amiloride analog 5-N-dimethylamiloride. The Na+/H+ exchanger in these membrane vesicles is activated allosterically by low intravesicular pH. The apparent pKa of the activating site is 6.4-6.6, characteristic of the NA+/H+ exchanger before activation by mitogens.