Evaluation of right ventricular functions in patients with nasal polyposis: an observational study/Nazal polipozisli hastalarda sag ventrikül fonksiyonlarinin degerlendirilmesi: Gözlemsel bir çalisma

Headnote

ABSTRACT

Objective: The aim of this study was to assess the right ventricular functions in patients with nasal polyposis using the strain (S) and strain rate (SR) echocardiography.

Methods: A prospective, cross-sectional observational study was performed. The study included 40 patients with nasal polyposis (NP) (Group 1), and 25 healthy controls (Group 2). The study comprised patients with Stage 2 and Stage 3 nasal obstruction and no symptoms that could be associated with right ventricular heart failure. Longitudinal peak systolic strain (PSS) and peak systolic strain rate (PSSR) were measured from the basal-mid and apical segments of the right ventricle free wall. Student's t-test, Pearson's correlation analysis and Bland-Altman test were used for statistical analysis.

Results: Pulmonary arterial systolic pressure was significantly higher in group 1 than group 2 (31.2±5.8, 19.7±4.3, respectively, p<0.001). PSS and PSSR values at the basal, mid and apical segments of the right ventricular lateral wall of the group I were significantly lower compared to the control group (p<0.001, p=0.002 and p=0.002 for PSS, p=0.003, p<0.001 and p<0.001 for PSSR, respectively). The comparison of Stage 2 and Stage 3 NP patients revealed a significant difference only in the SR measurement of the right ventricular mid segment (p=0.002). There was a signifi- cant correlation between the systolic pulmonary arterial pressure (sPAP) and right ventricular S and SR values (p<0.001).

Conclusion: In this study, S/SR echocardiography showed a subclinical deficit of the right ventricular longitudinal functions in patients with NP who are considered to have normal right ventricular functions. (Anadolu Kardiyol Derg 2013; 13: 251-6)

Key words: Nasal polyposis, right ventricular functions, strain/strain rate

ÖZET

Amaç: Bu çalifmada amaç nazal polipozisi olan hastalarda sag ventrikül fonksiyonlarini gerilme/gerilme hizi ekokardiyografi metodlari ile deger- lendirmektir.

Yöntemler: Çalifma enine kesitli gözlemsel prospektif olarak planlandi. Çalifmaya nazal polipozisli (NP) 40 hasta (Grup 1) ve saglikli 25 kontrol grubu (Grup 2) birey alindi. Hasta grubu nazal obstrüksiyonun seviyesi evre 2 ve evre 3 olan ve sag kalp yetersizligine bagli olabilecek herhangi bir semptomu olmayan hastalardan olufturuldu. Sag ventrikül serbest duvarinin bazal-mid ve apikal segmentlerinden longitüdinal pik sistolik strain (PSS) ve pik sistolik strain rate (PSSR) degerleri ölgüldü. Istatistiksel analizde Student-t test, Pearson korelasyon analizi ve Bland-Altman testi kullanildi.

Bulgular: Pulmoner arter sistolik basing Grup 1'de oldukça anlamli düzeyde daha yüksek bulundu (31.2±5.8, 19.7±4.3, p<0.001). PSS ve PSSR degerleri NP grubunda sag ventrikül lateral duvarinin bazal, mid ve apikal tüm segmentlerinde kontrol grubuna göre oldukça anlamli derecede düfük bulundu (PSS için sirasiyla; p<0.001, p=0.002 ve p=0.002, PSSR için sirasiyla; p=0.003, p<0.001 and p<0.001). Evre 2 ve evre 3 NP'li hastalar kendi aralarinda karfilaftirildiginda ise; yalnizca sag ventrikül mid-segmenti SR degerinde anlamli farklilik gözlendi (p=0.02). Sistolik pulmoner arteriyal basing (sPAP) yüksekligi ile sag ventrikül S ve SR degerleri arasinda oldukça anlamli düzeyde bir korelasyon oldugu görüldü.

Sonuç: Çalifmamiz, sag ventrikül (SV) fonksiyonlari normal olarak kabul edilen NP'li hastalarda S/SR ekokardiyografi ile SV longitüdinal fonksi- yonlarinda subklinik düzeyde bozulma oldugunu göstermiftir. (Anadolu Kardiyol Berg 2013; 13:251-6)

Anahtar kelimeler: Nazal polipozis, sag ventrikül fonksiyonlari, gerilme/gerilme hizi

Introduction

Nasal polyposis (NP) is a chronic inflammatory disorder of nasal and sinus mucosa with prominent nature of eosinophilia. This chronic inflammation results in a mass formation originating from mucosa of the sinus and prolapsing mostly through the lumen at the nasal mucosal surface (1). These mass formations leading to nasal obstruction are responsible from the clinical picture. This obstruction may also result in pulmonary hypertension (PH) and cor pulmonale (2). Nasopharyngeal muscles relax during sleep in patients with nasal obstruction. This relaxation increases the upper airway resistance during inspiration, leads to paralaryngeal collapse and hypoventilation, which end up with hypoxia and hypercapnia (3, 4). Chronic hypoxia and hypercapnia cause pul- monary arterial vasoconstriction and PH. If left untreated, this condition may lead to overloading, hypertrophy and dilatation of the right ventricle due to already increased pulmonary vascular resistance and pulmonary arterial pressure, which consequently causes right ventricular (RV) insufficiency and death (5, 6). Thus, early detection and treatment of myocardial disease are essential in such patients to prevent cardiopulmonary complications.

Tissue Doppler Imaging (TDI) is a technique, which is based on the demonstration of the movement of myocardial tissue with the low-frequency and high amplitude by filtering the move- ments of blood components with high-frequency (7). Strain (S) and strain rate (SR) echocardiography, which have been derived from myocardial colored TDI technique are clinically significant parameters and measure the global and regional myocardial functions rapidly and accurately (8). Studies on S/SR echocar- diography techniques to investigate the RV functions have shown that these imaging techniques are convenient and effec- tive in displaying the RV functions (9). They have suggested that S/SR echocardiography detects patients who are missed with conventional echocardiography, at an early subclinical stage.

We thought that, because of the hypoxia, hypoventilation and hypercapnia, right ventricular functions in patients with nasal polyposis could be affected in myocardial tissue level. To our knowledge, this hypothesis has not been confirmed before in the literature.

The aim of this study was to assess the right ventricular functions using S/SR echocardiography parameters in patients with nasal obstruction due to NP for at least one year.

Methods

Study design

A cross-sectional prospective observational trial was per- formed at Department of Ear, Nose and Throat, in Atatürk University, School of Medicine, Erzurum, Turkey between June 2009 and July 2010.

Patient selection

Consecutive 40 patients (Group 1) who presented with diag- nosis of NP and 25 healthy controls (Group 2) were enrolled in the study. The patients younger than 18 years and older than 45 years, those with a nasal pathology obstructing the nasal pas- sage, diabetes mellitus, hypertension, chronic obstructive lung disease, asthma and known coronary artery disease were excluded. Age-and gender-matched controls were recruited from among healthy patients attending the same hospital during the same study period.

Informed consent was received from all patients. The study protocol was approved by the Ethics Committee Atatürk University School of Medicine, Erzurum, Turkey.

Endoscopic examination

Nasal obstruction and NP diagnosis were based on history, symptoms, anterior rhinoscopy findings and endoscopic exami- nation. NP was staged according to endoscopic findings (10) such as Stage 0: No polyps, Stage 1: Mild polyposis, Stage 2: Intermediate polyposis, and Stage 3: Severe polyposis.

For endoscopic examination, 4 mm rigid 0 and 30-degree endoscope (Karl-Storz® GmBH&Co. Tuttlingen, Germany) were used. The study group comprised patients with Stage 2 or 3 nasal obstructions and without any symptoms that could be attributed to right heart failure.

Echocardiography

Echocardiographic measurements of the patients were done in the left lateral position with Vingmed ultrasound system (Vingmed System 7, General Electric, Horten, Norway) using a 2.5 MHz transducer, under single lead electrocardiography monitor- ization. The measurements were performed, independently, by two cardiologists unaware of the groups. Parasternal long axis and apical four chamber images were recorded according to the recommendations of the American Society for Echocardiography. Parasternal long axis images were used for left ventricular end- diastolic diameter (LVED), left ventricular end systolic diameter (LVES) and left atrial diameter (LA) measurements. Following this left ventricular ejection fraction (LVEF) was calculated using the Teicholz method. Right atrial (RA) and right ventricular diastolic (RV) diameters were measured based on apical four chamber images (11). Systolic pulmonary arterial pressure (sPAP) was cal- culated with the simplified Bernoulli equation, by adding the right atrial pressure value (10 mmHg) to the value calculated using the tricuspid flow velocity, considering the diameter of vena cava inferior and the level of its collapse resultant from respiration. In the apical four -chamber imaging, pulse wave Doppler sampling volume was placed on the interception point of the right ventricle lateral wall with the tricuspid annulus and the peak systolic myo- cardial velocity (Sm), diastolic early (Em) and late (Am) wave- lengths were recorded (Fig. 1).

Strain/Strain rate imaging

First, the RV free wall was visualized parallel to the trans- ducer in 2-dimensional imaging and the tissue velocity imaging (TVI) function frame rate was considered >100/s. Images were obtained with the minimum possible angle and maximum frame rate, only including the RV free wall. Images including three consecutive sinus beats at end of the expiratory stage were digitally recorded. The colored Doppler myocardial images were analyzed offline using software (EchoPC, GE Vingmed, Horten, Norway). Longitudinal peak systolic strain (PSS) (Fig. 2) and peak systolic strain rate (PSSR) (Fig. 3) were measured at the RV free wall basal-mid and apical segments (12). Distance between the two measured points was chosen as 10 mm. Three segments were analyzed for each individual in both groups. Measurements were performed two times on separate days, and average values were taken. Weak images and segments with an angular differ- ence >30 degrees were excluded from the study.

Statistical analyses

Data were analyzed with SPSS 11.0 (Statistical Package for Social Sciences, SPSS Inc., Chicago, IL, USA). The Kolmogorov- Smirnov test was used to evaluate whether the variables were normally distributed. The continuous variables were expressed as mean±standard deviation; categorical data were expressed as percent (%). Student's t-test was used to compare paramet- ric variables between the patient and control groups, Chi-square test - categorical variables, and Pearson's correlation analysis was used to assess the correlation between pulmonary arterial systolic pressure and S and SR parameters. Inter-observer and intra-observer agreements were assessed by Bland-Altman analysis. A p value <0.05 was considered statistically significant.

Results

Age, gender, body mass index (BMI), and systolic and dia- stolic blood pressures were similar in both groups. In echocar- diographic examination, LVED dimension, interventricular sep- tum (IVS) thickness, LA, RA and RV diameters were similar in both groups. LVEF displayed no difference between the two groups whereas LVED dimension was significantly higher in Group 1 than Group 2; on the other hand, PAPs was significantly higher in Group 1 (p<0.001). The demographic and echocardio- graphic data for groups were listed in Table 1. TDI findings from the right ventricular lateral wall tricuspid annulus revealed that Sm, Em and Am velocities were similar in both groups (Table 2).

Assessment of strain rate and strain values

PSS and PSSR values from the RV lateral wall basal, mid and api- cal segments were significantly lower in the NP group compared to the control group. The total rate of segments that could not be exam- ined in patient and control groups was 3% for S and 7% for SR. Moreover, intra-observer and inter-observer variables were computed 5% and 7.2%, respectively. PSS and PSSR values for all segments and their statistical comparisons were demonstrated in Table 3.

Comparison of Stage 2 and Stage 3 NP patients revealed that only the SR value for the RV mid-segment was significantly dif- ferent (p=0.02); other segments did not show a significant differ- ence in S and SR values (Table 4).

Pulmonary arterial pressure level was inversely correlated with RV S and SR values in all segments (Table 5).

Discussion

This study showed a subclinical level of impairment on right ventricular functions with S/SR echocardiographic methods in patients with NP.

Cardiovascular complications of NP are attributed to the chronic upper airway obstruction. Chronic alveolar hypoxia may lead to hypoxemic pulmonary vasoconstriction within time, which may result in hypertension and right ventricular heart failure (6, 13, 14). Chronic upper airway obstruction will increase the pressure load of the right ventricle and this in turn will lead to hypertrophy and subendocardial ischemia by increasing the RV wall tension, which eventually ends up with RV dysfunction (15). Pulmonary hypertension may not be an early sign. Fuster et al. (16) reported that the mean time from initial symptoms to diagnosis was 1.9 years in patients with PH. Thus, early diagno- sis is of utmost importance in such patients.

Echocardiography is the method of choice to assess RV func- tions in daily practice. Studies assessing RV functions have shown that the TDI technique is practical and handy, and has potential value (17, 18). However, TDI has some limitations such as the nega- tive effect on velocity of the increasing distance between the heart and the probe due to the elongation of the myocardium, transfer of active and passive deformation in neighboring segments and res- piration (8). S and SR techniques have been developed from tissue Doppler velocities to overcome those problems. Recent studies have suggested that S/SR echocardiography methods are superior to tissue Doppler velocities in assessing myocardial functions (19- 21). The assessment of RV longitudinal functions in our study revealed that while the Sm, Em and Am values did not display a significant difference between the patient and the control groups in the tissue Doppler arm, S/SR parameters revealed that the RV functions were significantly decreased in the patient group com- pared to the control patients.

Although the PAPs values of the patients were intermedi- ately increased (31.2±5.8) in our study group, they had no symp- tom attributable to RV insufficiency. Moreover, RA and RV diam- eters were within normal range in conventional echocardiogra- phy (34.6±4.6 mm and 34.5±4.0 mm respectively). Our patient and control groups had similar clinical and conventional echocardio- graphic findings. However, examination with S/SR echocardiog- raphy revealed a subclinical dysfunction in the patient group. Moreover, there was a significant negative correlation between the PAPs and S/SR values in the RV basal-mid and apical seg- ments. In other words, S/SR values decreased as the PAPs increased. Early detection of such findings may be fundamental for the treatment of patients with NP.

Studies about the value of S/SR echocardiography tech- niques to assess RV functions have reported that these methods are practical and effective to show RV functions. Vitarelli et al. (22) categorized patients with obstructive lung disease and PH according to their PAPs values as Group 1 (<35 mmHg) and Group 2 (>35 mmHg) and compared them with healthy controls. They found that the decrease in RV S/SR values were correlated with the extent of PAPs and pulmonary function test results and they suggested that S/SR values might be clinical prognostic markers of RV insufficiency. Lopez-Candales et al. (23) reported that the RV longitudinal free wall S values were significantly decreased in patients with a high mean pulmonary arterial pres- sure (78±24 mmHg) compared to healthy individuals. A review by Gondi et al. (9) on the clinical usefulness of RV TDI suggested that all data obtained by comparing various patient populations revealed that TDI was an acceptable, reproducible and practical additional echocardiographic parameter in assessing RV sys- tolic and diastolic functions. However, they suggested that such patients had subclinical conditions that could not be detected with conventional echocardiography.

Study limitations

Similar to previous studies, the major limitation in our study was angle dependence and artifacts. The angle difference increases from the basis to the apical part of the heart. The amount of deformation increases when the angle difference exceeds 30 degrees. We took care to keep the tissue direction less than 30 degrees and parallel to ultrasound waves. Besides, we tried to keep the frame rates high to decrease the margin of error. Lack of magnetic resonance imaging and/or invasive tech- niques, which are considered the gold standard in the assess- ment of RV functions, is another major limitation. However, studies have shown that S/SR parameters correlate well with invasive hemodynamic parameters. Other limitation is relatively small number of patients included in this study.

Conclusion

The results of our study suggest that NP patients who are clinically asymptomatic and have normal RV functions with con- ventional echocardiography have subclinical RV longitudinal dysfunction with S/SR echocardiography. S/SR echocardiogra- phy may be used as a reliable determinant of RV systolic func- tions in patients with no right heart failure findings.

Conflict of interest: None declared.

Peer-review: Externally peer-reviewed.

Authorship contributions: Concept - E.§., Z.§.; Design - Z.§.; Supervision - Z.§.; Resource - C.K., H.Ü., E.§.; Materials - M.H.T.; Data collection&/or Processing - M.H.T., E.§.; Analysis &/or inter- pretation - M.H.T., E.§.; Literature search - C.K., E.G.; Writing - Z.§., E.G.; Critical review - E.G., H.Ü.; Other - C.K.

Kalbi mercuha haber vermi sakun yaresini

kayuver cirpina dursun arasin caresini

Bozma gel hasta ile hastaligin aresini

Belki allah yaratir caresizin caresini

Na umit etme tabip hastayn dermanindan

ihtiraz uzre bulun his lyle iz anindan

kezmez umidini kul rabbinin ihsanindan

Belki allah yaratar caresizin caresini

Dr. Ali Pasa

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