INTRODUCTION

Portal hypertension is the increase of portosystemic pressure in any segment of the portal venous system, caused by pre-hepatic or post-hepatic alterations or by other causes¹. It occurs when the portocaval gradient is higher than 5 mmHg and is the most frequent and studied cause of hepatic cirrhosis. From 5 to 33% of these patients have varices, which may appear at any part of the gastrointestinal tract, the most frequent site being the distal centimeters of the esophagus. The presence of varices is correlated with the severity of liver disease^1,2. The hepatic venous pressure gradient is the ratio between portal pressure and vena cava pressure and predicts the appearance of varices. Clinically significant portal hypertension is 10 mmHg, and is a prognosis factor in patients suffering from portal hypertension¹.

When the gradient reaches 12 mmHg, variceal hemorrhage occurs. The main risk factors are: international normalized ratio (INR) greater than 1.5, portal vein diameter greater than 13 mm, and thrombocytopenia. When the patient has one or more of these conditions, it is necessary to perform upper gastrointestinal endoscopy to look for varices and to perform primary prophylaxis against bleeding in cirrhotic patients^1-3.

In upper gastrointestinal bleeding (UGH), endoscopy has a high sensitivity and specificity in locating and identifying lesions that cause bleeding. In addition, it offers the possibility of a therapeutic approach and primary prophylactic treatment^2,4,5.

Certain noninvasive tests are useful in detecting patients at risk of esophageal varices. These include platelet count, splenomegaly, portal vein diameter greater than 13 mm by abdominal ultrasound and lately elastography. However, none of these tests has diagnostic accuracy for large esophageal varices^1,6,7.

The platelet count/spleen bipolar diameter (P/B) ratio of less than 909 is a non-invasive parameter that predicts the presence of esophageal varices in cirrhotic patients⁸. It can be a diagnostic and follow-up alternative to endoscopy, which is expensive and difficult to access, and may be contraindicated in some patients^8,9.

The objective was to determine the sensitivity and specificity of the platelet count/spleen major diameter (P/B) ratio for the diagnosis of esophageal varices with risk of bleeding in patients with liver failure.

Findings

Seventy patients were recruited. The sample was predominantly male and geriatric patients. The characteristics in terms of sex, age and etiology of liver disease are shown inTable 1.

The average age was 59.58, minimum 35, maximum 85, SD=10.92 years. Regarding age groups, 3 (4.3%) patients were in the 18 to 40 years old group, 28 (40%) in the 41 to 60 years old group and 39 (55.7%) patients in the group older than or equal to 61 years old.

Regarding Child-Pugh classification, stage B was the most frequent with 32 (45.7%) patients. Details are shown in Figure 1.

According to the Dagradi classification for esophageal varices⁽³⁾, there were 21 (30%) Grade III patients. The rest of the details can be seen in Figure 2.

The correlation between P/B and Child-Pugh was 0.723, p<0.05, and between P/B and Dagradi was 0.585 (p<0.05), (a value of p<0.05 Spearman was considered statistically significant).

Of the 70 patients included in the sample, 47 (67%) patients presented esophageal varices at endoscopy and positive P/B index, 5 (7%) presented positive endoscopy for esophageal varices and 1.4% of patients presented negative P/B, with the following results: sensitivity 90%, specificity 83%, false positives 16%, false negatives 9%, positive predictive value of 94%, a negative predictive value of 75%, prevalence of 74% and a diagnostic certainty of 88% for P/B as a predictor of esophageal varices with risk of bleeding (Table 2).

Table 1.  Population characteristics. 

Sex Etiology	Men	Women
Virus hepatitis C	0	20
Virus hepatitis B	0	1
Etilism	31	0
Unidentified	11	7
Total	42	28
Total of patients=70

Table 2.  Comparison of the P/B index with endoscopy results. 

			Endoscopic result				TOTAL
		+	-
Índice P/B <909	+	47	3	50
	-	5	15	20
TOTAL			52		18		70

SENSIBILITY = a/(a+c) = 0,90 (90%).

FALSE POSITIVES = b/(b+d)=0,16 (16%).

POSITIVE PREDICTIVE VALUE = a/(a+b)=0,94 (94%).

PREVALENCE = (a+c)/(a+b+c+d) = 0,74 (74%).

SPECIFICITY = d/(b+d) = 0,83 (83%).

FALSE NEGATIVES = c/(a+c) =0,09 (9%).

NEGATIVE PREDICTIVE VALUE = d/(c+d) =0,75 (75%).

DIAGNÓSTICA CERTAINTY = (a+d)/(a+b+c+d) = 0,88 (88%).

AbreviatIons: + = positive, - = negative, P/B = platelets/spleen.

Figure 1: Distribution of patients according to Child-Pugh classification 

Figure 2: Distribution of patients according to Dagradi classification 

DISCUSSION

Portal hypertension is the main complication of chronic liver diseases that develop cirrhosis. It can cause esophageal varices in up to 30% of patients^1,6-9,12. The most frequent causes are viral, alcoholic and of unidentified cause¹.

Endoscopy is the diagnostic method of choice in HDA, it has high sensitivity and specificity since it records and identifies the location of the lesions that cause bleeding in the esophagus, stomach and duodenum. Nowadays, it is still the most accurate technique for diagnosing and staging esophageal varices, especially those of grade I, and for visualizing signs of risk for hemorrhage. This method provides the diagnosis and offers the possibility of a therapeutic approach^4,5,13.

The frequency of bleeding esophageal varices is 100 in every 100,000 persons per year; it is a medical emergency associated with high mortality, especially in older adults^1-3,5-9.

Esophageal varices, which occur in 100 out of every 100,000 persons per year, are a medical emergency associated with high mortality, especially in older adults^{1-3,5-9,13,14}.

However, since endoscopy is an invasive diagnostic method, it has both relative and absolute contraindications. In developing countries, the availability of an endoscopic study is limited, therefore, different less invasive methods such as the P/B index have been implemented^4,6-9,13,14.

The P/B index is inexpensive, is run quickly and requires no major skills for its performance. It is seen as a safe alternative in countries with limited economic resources that do not have endoscopy services, and another advantage is that it can be calculated rapidly^6,8,13-15.

Since 2003, the high value of P/B has been demonstrated, even in the subgroup of patients with compensated liver disease⁶.

The value of P/B 909 or lower has been considered an indicator of esophageal varices^(6,8,14,15). Reports in the Latin American population range from acceptable to very good for sensitivity, specificity and positive and negative predictive values^8,14,15. In this study the results of the test in comparison with endoscopy were very high in sensitivity (90%), specificity (83%) and positive predictive value (94%), but low in negative predictive value (75%).

Some studies carried out in the Mexican population report a moderate correlation between P/B and esophageal varices: a P/B value greater than 0.7 correlated with Baveno grade I varices (<5 mm), and less than 0.7 with grade II varices (>5 mm) and with a low predominance in the advanced stages of Child-Pugh (of liver function) and Dagradi (of esophageal varices)¹⁴.

In this study, in which 70 patients were included, there was a higher correlation between P/B and Dagradi, with a higher percentage of patients in Child-Pugh stages B and C, compared to other studies.

As mentioned above, performing endoscopy for esophageal varices screening every one to two years in high-risk patients can be difficult and impractical⁹. Non-invasive parameters associated with high-risk esophageal varices help to reduce the need for endoscopic studies to be performed at this frequency and can be used to distinguish between high- and low-risk patients. This could be used to follow up only high- or very high-risk patients with endoscopic studies^6,9,10,12.

It is also necessary to mention that a diagnostic endoscopy for esophageal varices should be performed in patients with risk factors, such as a Child-Pugh A^12,13,15.

However, the P/B index is useful for stratification of cirrhosis patients into risk categories where portal hypertension data exist. This is especially relevant for those patients whose health status and conditions do not allow an invasive study, but who are at high risk of developing esophageal varices^6,9,10,12.

In this study, most of the patients had Child-Pugh B and C classification. These stages are those with the highest risk to be associated with esophageal varices and bleeding according to international literature^9,12-15.

The results of the test performed on the P/B index are consistent with other studies, although some show wide ranges of variability among them^6,8,13-15.

The P/B is strongly associated with the presence of esophageal varices^1,6,13,14, and its negative predictive value is reproducible, in this study with 75% and with a diagnostic certainty of 88%.

CONCLUSION

In conclusion, the P/B index presents false negatives of 9%, with a positive predictive value of 94%, a negative predictive value of 75%, with a prevalence of 74% and a diagnostic certainty of 88%, so it can be considered a useful and non-invasive study to diagnose esophageal varices especially in places, without availability of endoscopy.